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.