With respect to each employee of a retail or service establishment exempt from the overtime pay requirements of the Act pursuant to the provisions of section 7(i), employers shall maintain and preserve payroll and other records containing all the information and data required by § 516.2(a) except paragraphs (a) (6), (8), (9), and (11), and in addition:
(a) A symbol, letter or other notation placed on the payroll records identifying each employee who is paid pursuant to section 7(i).
(b) A copy of the agreement or understanding under which section 7(i) is utilized or, if such agreement or understanding is not in writing, a memorandum summarizing its terms including the basis of compensation, the applicable representative period and the date the agreement was entered into and how long it remains in effect. Such agreements or understandings, or summaries may be individually or collectively drawn up.
(c) Total compensation paid to each employee each pay period (showing separately the amount of commissions and the amount of noncommission straight-time earnings).