I believe that GAAP requires accounting for work expenses at the time when the work is performed - e.g. the salary due for last week of March must be counted in March, no matter if you issued a paycheck right at the end of week or haven't paid it yet for whatever reasons.

Though, one way for companies to game the system in GAAP is to be late in paying their employees & contractors by having part of their renumeration be in stock options - people perceive it as compensation, but it can be excluded from GAAP since the value technically doesn't come from "within the company" but from reducing the value of other shareholders.