29 CFR § 778.327 - Temporary or sporadic reduction in schedule.
(a) The problem of reduction in the workweek is somewhat different where a temporary reduction is involved. Reductions for the period of a dead or slow season follow the rules announced above. However, reduction on a more temporary or sporadic basis presents a different problem. It is obvious that as a matter of simple arithmetic an employer might adopt a series of different rates for the same work, varying inversely with the number of overtime hours worked in such a way that the employee would earn no more than his straight time rate no matter how many hours he worked. If he set the rate at $6 per hour for all workweeks in which the employee worked 40 hours or less, approximately $5.93 per hour for workweeks of 41 hours, approximately $5.86 for workweeks of 42 hours, approximately $5.45 for workweeks of 50 hours, and so on, the employee would always receive (for straight time and overtime at these “rates”) $6 an hour regardless of the number of overtime hours worked. This is an obvious bookkeeping device designed to avoid the payment of overtime compensation and is not in accord with the law. See Walling v. Green Head Bit & Supply Co., 138 F. 2d 453. The regular rate of pay of this employee for overtime purposes is, obviously, the rate he earns in the normal nonovertime week - in this case, $6 per hour.
(b) The situation is different in degree but not in principle where employees who have been at a bona fide $6 rate usually working 50 hours and taking home $330 as total straight time and overtime pay for the week are, during occasional weeks, cut back to 42 hours. If the employer raises their rate to $7.65 for such weeks so that their total compensation is $328.95 for a 42-hour week the question may properly be asked, when they return to the 50-hour week, whether the $6 rate is really their regular rate. Are they putting in 8 additional hours of work for that extra $1.05 or is their “regular” rate really now $7.65 an hour since this is what they earn in the short workweek? It seems clear that where different rates are paid from week to week for the same work and where the difference is justified by no factor other than the number of hours worked by the individual employee - the longer he works the lower the rate - the device is evasive and the rate actually paid in the shorter or nonovertime week is his regular rate for overtime purposes in all weeks.