ARNOLD, Circuit Judge.

This is a price-discrimination case under section 2 of the Clayton Act, as amended by the Robinson-Patman Act, 15 U.S.C. § 13(a). The jury found that Ambrosia Chocolate Co. violated the Act, and it awarded plaintiff Rose Confections, Inc., $545,500 in damages. The District Court trebled the damages under section 4 of the Clayton Act, 15 U.S.C. § 15, and entered judgment against Ambrosia for $1,636,500. After the District Court denied Ambrosia's motion for a new trial or judgment n.o.v., Rose Confections moved for $340,812.49 in attorney's fees and costs under section 4; the District Court awarded $195,852.99. In No. 86-5011 Ambrosia appeals from the judgment and from the denial of its motion for a new trial or judgment n.o.v., and in No. 86-5079 it appeals from the award of fees and costs. We affirm the jury's finding of liability under the Robinson-Patman Act, but we reverse the judgment and remand for a new trial on damages. Of the two damages theories Rose Confections presented at trial, one was erroneous as a matter of law because it assumed that Rose received the same price that it claimed, and the jury found, to be discriminatory. A correct theory would have been based, instead, on an assumption that neither Rose nor its favored competitor had received a price concession from Ambrosia. Since we reverse the judgment and remand for a new trial on damages, we also reverse the award of attorney's fees and costs and remand for redetermination in light of the additional proceedings.

*384 I.

Ambrosia, the nation's largest manufacturer of cocoa-based products at the time of trial, makes a wide range of chocolate products at plants in Milwaukee, Wisconsin, Newark, New Jersey, and Charlotte, North Carolina. Tr. VI:538. We are concerned with only one of its products-chocolate chips. Ambrosia sells chips to industrial customers for use as ingredients in other products, such as ice cream and baked goods, and to “rebaggers,” who package bulk chips in 12-18 ounce bags and sell them to retailers, such as grocery chains. Rose Confections is a rebagger located in Plymouth, Minnesota. It sells rebagged chips under its own “control” label, “Log House” (which is the company's present corporate name), and under the “private” labels of many of its retail customers, such as Jewel Foods in Chicago. Tr. II:65. Barg & Foster, one of Rose Confections' primary competitors in the private-label market, is a rebagger with facilities originally in Milwaukee. Before 1980, both Rose Confections and Barg & Foster bought the great majority of their bulk chips from Ambrosia.

The product market here is the market in rebagged, private-label chocolate chips. Rebagging private-label chips is essentially a process of buying bulk chips from a manufacturer, making cellophane bags bearing the retailer's private label, and sealing the chips in the bags. The most significant direct costs of production are the cost of the bulk chips, the cost of transporting them from the manufacturer to the rebagging facility (called “freight in”), and the cost of transporting the finished product from the plant to the retail customer (called “freight out”). Tr. II:127. Thus a rebagger has a competitive advantage over other rebaggers if it is located close to its source of supply or close to its retail customer, so that it can eliminate these freight costs. Tr. II:91-92; III:215. Similarly, a chocolate-chip manufacturer has a competitive advantage over other manufacturers if it is located near rebaggers who sell in high-volume markets. In addition to freight savings, having a plant near the customer enables a seller, either a manufacturer selling to a rebagger, or a rebagger selling to a retailer, to provide better service and to fill orders more quickly, both of which are important factors in the private-label chip market. Tr. VI:540-41; III:224.

The geographic market involved is the West Coast of the United States, which, the parties agree, includes California, Oregon, Washington, Nevada, and Arizona. Before 1980, Ambrosia, Rose Confections, and Barg & Foster each sold their products, with varying degrees of success, in the West Coast. Ambrosia had a strong position in the markets near its plants in the Midwest, Southeast, and East Coast, but it was in a “precarious” position in the West Coast market because it did not have a manufacturing location there. Addendum to Appellant's Brief (“Add.”), at A14.2; Tr. VI:538-41. In 1980 it decided to “buy” sales on the West Coast by reducing its prices to West Coast customers, with the goal of raising its West Coast sales to a volume that would justify building a manufacturing plant there. Add. at A14.2; Tr. VI:542-43. The price reduction took the form of a “freight absorption”; on sales to West Coast customers from its Milwaukee plant, Ambrosia would charge the same price that it charged other buyers, but it would deliver the product for free to the customers' West Coast facilities. On sales to other buyers, the buyers had to pay for shipping. Ambrosia called this strategy its “West Coast project,” and it made this offer to three West Coast customers during 1980 and early 1981. Tr. VI:607-10. None of these, however, was a rebagger.

In spring 1981, Ambrosia approached Barg & Foster with the proposal that is at the center of this lawsuit: If Barg & Foster would build a rebagging plant on the West Coast, Ambrosia would sell Barg & Foster chips under the terms of the “West Coast project.” Joint Appendix (“J.A.”) at 7. By contrast, its existing supply contracts with Barg & Foster and Rose Confections called for delivery F.O.B. Ambrosia's Milwaukee plant, with no option for delivery to the buyer's plant. Tr. III:278. Under this new agreement, Barg & Foster *385 established a rebagging plant at Sparks, Nevada and took delivery of more than 5 million pounds of freight-free chips there between July 1981 and October 1983.FN1 Ambrosia never offered a similar deal to Rose Confections. As a result, Rose Confections competed directly against Barg & Foster in the West Coast private-label market for more than two years while at a two-pronged competitive disadvantage. First, Rose Confections had to pay freight-in costs from Milwaukee to Plymouth, while Barg & Foster did not have any freight-in costs at its Sparks plant. The freight savings to Barg & Foster amounted to about $1 per case of finished product, or $309,609.48 in all. Tr. III:215, 275; J.A. at 10.3. Second, Rose Confections had higher freight-out costs from Plymouth to its West Coast customers than did Barg & Foster, which could ship from Sparks.

FN1. The agreement was reached in April 1981 and was originally to last until the end of 1982. J.A. at 7. Later, Ambrosia and Barg & Foster agreed to include this provision in all unfilled orders that had been placed after January 1, 1981, which in effect made the agreement retroactive to that time. Tr. III:277-78. On September 22, 1982, Ambrosia extended the agreement through July 31, 1983. J.A. at 9. The last free-freight delivery to Sparks from Ambrosia was on October 3, 1983. J.A. at 10.3.

Rose Confections brought its Robinson-Patman action against Ambrosia, but not Barg & Foster, alleging that the free-freight arrangement was an illegal price discrimination that injured secondary-line competition between Rose Confections and Barg & Foster in the West Coast market. After a jury trial over the course of two weeks, the jury returned a damages verdict in favor of Rose Confections.

Ambrosia attacks the judgment and the award of fees and costs on many different fronts. In the next two parts of the opinion, we discuss the issues relating to liability under the Robinson-Patman Act. We affirm on those issues. Then we discuss the issue on which we reverse and remand for a new trial, Rose Confections' damages under section 4 of the Clayton Act. Finally, we discuss the award of attorney's fees and costs.

II.

To establish liability under the Robinson-Patman Act, one of the elements that plaintiff must demonstrate is a reasonable possibility that the price discrimination may substantially injure competition. This burden may be met in two ways. First, plaintiff may introduce direct evidence that disfavored competitors lost sales or profits as a result of the discrimination. See Falls City Industries, Inc. v. Vanco Beverage, Inc., 460 U.S. 428, 437-38, 103 S.Ct. 1282, 1290, 75 L.Ed.2d 174 (1983). Second, he can show that the favored competitor received a substantial price reduction over a substantial period of time, which gives rise to a permissible inference of competitive injury. FTC v. Morton Salt Co., 334 U.S. 37, 50-51, 68 S.Ct. 822, 830-31, 92 L.Ed. 1196 (1948). Ambrosia argues that Rose Confections' evidence fails under either standard. We disagree.

A.

There was direct evidence at trial that Rose Confections lost profits and sales as a result of the freight absorption. Rose Confections' president, Alan Kasdan, testified that his company had to reduce prices to its customers on the West Coast in response to low-price offers made by Barg & Foster. FN2 Its West Coast sales broker, John *386 Pfeifer, testified by deposition that Rose Confections lowered its price to one of its longstanding West Coast clients, Ralph's Supermarket, as a result of price competition from Barg & Foster. Pfeifer Depo. at 14-17. Mr. Kasdan also testified to this price reduction. Tr. II:157-59. There was also testimony that Rose Confections lost potential clients to Barg & Foster because of these lower prices. Mr. Pfeifer stated that Rose Confections unsuccessfully solicited the accounts of Thrifty Drug, Sav-On Drugs, and Fedmart, and, after the solicitations, the stores carried chips prepared by Barg & Foster. Pfeifer Depo. 18-21. In addition, Mr. Kasdan related Rose Confections' extensive, seven-year efforts to obtain the largest West Coast account, Safeway, which he thought it had finally won:

FN2. Mr. Kasdan testified on direct examination:

Q: After [Barg & Foster's Sparks plant became operational], did you become aware of any change, or price pressure, I should say, in competition with Barg and Foster in the West Coast?

A: Yes.

Q: When was the first time?

A: In the fall of '81, I began to receive calls from my brokers and customers, telling me that there were extremely competitive prices being offered by Barg and Foster.

Q: When you got that information, what did you do?

A: I called [the] Ambrosia sales manager that handled Barg and Foster and us.

Q: What did you say ... when you called him?

A: I told him I was receiving extreme competition from Barg and Foster on the West Coast, and I didn't understand it, because they were selling at prices so low that it appeared to be they were selling below my cost. I couldn't understand how they could do that....

Tr. II:134-35.

Q: What was happening to prices in the market in terms of the price that you could sell the products for in ... 1981, 1982, '83 ...?

A: Prices were extremely competitive. It was tremendous competitive price pressure.

Q: What do you mean by that?

A: Barg and Foster was extremely competitive on their prices. They are very, very aggressive in going out and offering prices. Ghiradelli pretty much responded the way they normally did. They were sort of passive. And toward the fall of 1982, Ambrosia's Retail Services Division began offering some very competitive prices as well in the California market.

Q: Now, how did these prices square with the pricing formula that you were generally attempting to meet in doing business in the West Coast, ...?

A: The prices were more representative of our prices in the Middle West than they were on the West Coast. They were much lower than what they should have been for the freight cost out there.

Q: Did you attempt to remain active and to preserve a position in the West Coast market notwithstanding this price activity?

A: Absolutely.

Q: What did you do?

A: We worked that much harder trying to get new customers, compete. We were forced in many cases to cut our margins and our profit, and sometimes to no margin at all, to retain the business on accounts. And we became much more competitive or aggressive in trying to acquire new accounts.

Q: What happened to your profit margins in sales to the West Coast market during that period ...?

A: Our profit margin diminished during that period....

Tr. II:144-45.

Q: At the time of the first offer, May of 1981, you had the private label account at Safeway?

A: That's correct.

Q: And by the fall of '81, you learned that Barg and Foster had the account?

A: That's correct.

Tr. II:142-43.

Barg & Foster's president during that time, Arlan Kitsis, testified that it submitted a low-price offer, reflecting its freight savings, to Safeway to win the account:

Q: Did you after the Sparks facility was planned and [as] part of your program then attempt to sell the Safeway business?

A: Yes.

Q: And in attempting to sell the Safeway business, did you submit a price to them?

A: Of course.

Q: And did that price which was determined by your company reflect the advantages afforded your company by the freight equalization program given by Ambrosia?

A: I would imagine so.

Q: But it did?

A: How would it not?

Tr. III:216.

This evidence alone is sufficient to allow a reasonable juror to find competitive injury. Ambrosia argues that this evidence is insufficient to satisfy the competitive-injury requirement for three reasons. First, Mr. Kasdan admitted that Rose Confections did not lose a single sale to Barg & Foster from any of its existing customers (those who had been Rose Confections' clients before the Sparks plant was opened). But it was still sufficient proof of competitive injury for Rose Confections to show that it lowered prices to existing customers and lost potential customers as a *387 result of the freight absorption.FN3 Second, Rose Confections' West Coast market share increased substantially despite the alleged price discrimination, and Ambrosia points to this as proof that there was no competitive injury. The Supreme Court, however, has held that a jury may find competitive injury in spite of an increase in plaintiff's market share during the relevant time. Utah Pie Co. v. Continental Baking Co., 386 U.S. 685, 702, 87 S.Ct. 1326, 1335, 18 L.Ed.2d 406 (1967). Finally, Ambrosia argues that Rose Confections' evidence of lost prices shows that it “reduced prices to West Coast customers only on a selective basis, and then only to meet the competition of rebaggers generally,” Appellant's Brief at 31, rather than competition from Barg & Foster. It is true that factors other than Barg & Foster's low prices may have led to Rose Confections' price reductions. But to the extent that this is so, it goes only to the amount of damages for which Ambrosia is liable under section 4, not to the showing of competitive injury under section 2(a). So long as there is a discrimination, the effect of which “may be substantially to lessen competition,” the section 2(a) requirement is satisfied even though other factors may in fact have contributed to plaintiff's injury. See Falls City, 460 U.S. at 437, 103 S.Ct. at 1290. Section 4 protects a Robinson-Patman defendant from liability in damages for an injury that he did not in fact cause. See J. Truett Payne Co. v. Chrysler Motors Corp., 451 U.S. 557, 561-63, 101 S.Ct. 1923, 1926-28, 68 L.Ed.2d 442 (1981).

FN3. Although Ambrosia does not make this claim, it could be argued that Rose Confections' direct evidence of competitive injury shows only injury to a competitor (Rose Confections), rather than to competition generally. If so, the evidence would be insufficient, for it is settled that the Robinson-Patman Act guards against injury to competition, not injury to individual competitors. Henry v. Chloride, Inc., 809 F.2d 1334 (8th Cir.1987). But that is not the case here. The record reveals that there was at least one other private-label rebagger who bought chips from Ambrosia and sold on the West Coast and was not offered the freight absorption. Tr. VI:615-17. In this light, we think that Rose Confections' evidence of its own lost sales and profits would support a jury finding that other