58.3. Where an individual, because of membership in a trade union or association referred to in paragraph 1 of section 172, participates in activities of the union or association and, as a consequence, is unable to perform duties, under a contract of employment, for the individual’s employer during a period during which the individual would, were it not for the individual’s participation in those activities, be obligated to provide such services, and the union or association pays an amount to the employer as compensation for expenses incurred by the employer as a consequence of the individual’s participation in those activities or for remuneration or benefits given by the employer to the individual in respect of that period, the amount is deemed not to be consideration for a supply.