When will an award for attorney fees be reduced based on allocation?

The legal principles governing the determination of whether a fee award should be reduced based on allocation are well established. "'Where a plaintiff has obtained excellent results, his attorney should recover a fully compensatory fee. Normally this will encompass all hours reasonably expended on the litigation, and indeed in some cases of exceptional success an enhanced award may be justified. In these circumstances the fee award should not be reduced simply because the plaintiff failed to prevail on every contention raised in the lawsuit.' (Hensley v. Eckerhart (1983) 461 U.S. 424, 435 . . . .)