(1) This section applies in working out the percentage of the decrease of hearing in relation to boilermakers deafness of an injured person who is the prescribed age or older, but does not apply to total hearing loss in either of the person's ears.
(2) For this part, it is to be conclusively presumed that the injured person's loss of hearing to be attributed to loss of hearing because of age is 0.5 decibels for each complete year of the person's age over the prescribed age.
(3) In this section:
"prescribed age "means—
(a) for a male—55 years old; or
(b) for a female—65 years old.