(a) The term extra payment shall mean a payment, in a specific amount, made in addition to the straight-time and overtime compensation which would be due the performer under the agreement applicable to his employment and under the Act if the time spent in performing the services or special services referred to in paragraph (a) of § 550.1 had been devoted exclusively to duties as a staff performer; but shall not include any payment any part of which is credited or offset against any remuneration otherwise payable to the performer under any contract or statutory provision;

(b) The term performer shall mean a person who performs a distinctive, personalized service as a part of an actual broadcast or telecast including an actor, singer, dancer, musician, comedian, or any person who entertains, affords amusement to, or occupies the interest of a radio or television audience by acting, singing, dancing, reading, narrating, performing feats of skill, or announcing, or describing or relating facts, events and other matters of interest, and who actively participates in such capacity in the actual presentation of a radio or television program. It shall not include such persons as script writers, stand-ins, or directors who are neither seen nor heard by the radio or television audience; nor shall it include persons who participate in the broadcast or telecast purely as technicians such as engineers, electricians and stage hands;

(c) The term special services shall mean services beyond the scope of a performer's regular or ordinary duties as a staff performer under the agreement applicable to the employment.