29 C.F.R. § 778.323

The discussion in the prior section sets forth one result of reducing the workweek from 40 to 35 hours. It is not either the necessary result or the only possible result. As in all cases of employees hired on a salary basis, the regular rate depends in part on the agreement of the parties as to what the salary is intended to compensate. In reducing the customary workweek schedule to 35 hours the parties may agree to change the basis of the employment arrangement by providing that the salary which formerly covered a fixed workweek of 40 hours now covers a variable workweek up to 40 hours. If this is the new agreement, the employee receives $200 for workweeks of varying lengths, such as 35, 36, 38, or 40 hours. His rate thus varies from week to week, but in weeks of 40 hours or over, it is $5 per hour (since the agreement of the parties is that the salary covers up to 40 hours and no more) and his overtime rate, for hours in excess of 40, thus remains $7.50 per hour. Such a salary arrangement presumably contemplates that the salary will be paid in full for any workweek of 40 hours or less. The employee would thus be entitled to his full salary if he worked only 25 or 30 hours. No deductions for hours not worked in short workweeks would be made. (For a discussion of the effect of deductions on the regular rate, see §§ 778.304 to 778.307.)