(a) In any case where a totally disabled person is presently receiving the maximum weekly income benefit applicable at the time such award was made, the adjusted award shall equal the new maximum weekly benefit.
(b) In any case where a totally disabled person is presently receiving less than the maximum weekly income benefit rate applicable at the time such award was made, a new weekly income benefit shall be computed by multiplying the new maximum by a fraction the numerator of which is his present award and the denominator of which is the maximum weekly rate applicable at the time such award was made.