28.—(1) If a person has been employed in any relevant employment and under the conditions of his service in that employment for all or any part of it worked for less hours than are normally worked by persons in that employment (excluding overtime) for the purpose of calculating compensation under these regulations his reckonable service shall be proportionately reduced.
(2) For the purpose of calculating compensation under these regulations:—
(a)periods of reckonable service shall be aggregated;
(b)if the total reckonable service amounts to a fraction of a year, or to a complete year or complete years and a fraction of a year, the fraction shall if it equals or exceeds six months be treated as a year, and if not shall be disregarded.