29 CFR § 779.418 - Grace period for computing portion of compensation representing commissions.
Where it is not practicably possible for the employer to compute the commission earnings of the employee for all workweeks ending in a prior representative period in time to determine the overtime pay obligations, if any, for the workweek or workweeks immediately following, 1 month of grace may be used by the retail or service establishment. This month of grace will not change the length of the current period in which the prior period is used as representative. It will merely allow an interval of 1 month between the end of the prior period and the beginning of the current period in order to permit necessary computations for the prior period to be made. For example, assume that the representative period used is the quarter-year immediately preceding the current quarter, and commissions for the prior period cannot be computed in time to determine the overtime pay obligations for the workweeks included in the first pay period in the current quarter. By applying a month of grace, the next earlier quarterly period may be used during the first month of the current quarter; and the quarter-year immediately preceding the current quarter will then be used for all workweeks ending in a quarter-year period which begins 1 month after the commencement of the current quarter. Thus, a January 1-March 31 representative period may be used for purposes of section 7(i) in a quarterly period beginning May 1 and ending July 31, allowing the month of April for necessary commission computations for the representative period. Once this method of computation is adopted it must be used for each successive period in like manner. The prior period used as representative must, of course, as in other cases, meet all the requirements of a representative period as previously explained.