20 CFR § 322.3 - Determining the days with respect to which remuneration is payable or accrues.
(1) The intention of the parties with respect to the remuneration as indicated in employment contracts, in any expressed or implied agreements between the parties, and by the actions of the parties;
(2) Any evidence, such as vouchers or agreement of the parties, relating the remuneration to a particular period of time or indicating that the remuneration accrued or became payable without reference to any particular period of time;
(3) The measure by which the amount of remuneration was determined;
(6) Whether a specified amount of the remuneration is contingent upon a result accomplished on a particular day or particular days.
(b) Layover days. Remuneration shall not be regarded as payable or accruing to an employee with respect to his or her “layover” days between regular assignments in train and engine service solely because they are termed “layover” days. But no such “layover” day may be considered as a day of unemployment or sickness. See § 332.6 of this chapter.
(c) Guaranteed earnings. A payment under a plan which guarantees an amount of earnings or mileage in a specified period is remuneration with respect to each day in the specified period.
(d) Equivalent of full-time work. An employee who works fewer than five days each week under a compressed work schedule that provides the equivalent of full-time employment does not earn remuneration with respect to his or her additional rest days resulting from such work schedule, but such employee will not be considered to be available for work on such rest days. See § 327.10(d) of this chapter.