43. (1) If it is established to the satisfaction of the Commission that a workman is disabled from working by reason of an aggravation consequent upon a workman’s accident which aggravation occurred more than one year after such accident, the indemnity in respect of the temporary disability shall be based on the earnings of the claimant at the time of the aggravation, as in the case of another accident, where such earnings are greater than those on which the previous compensation was based.
(2) When such aggravation causes a permanent disability, the indemnity shall be based on the earnings previous to the aggravation if such earnings are greater than those on which the previous compensation was based.
(3) In the cases provided in the last two subsections, the degree of disability for which the workman has already been compensated shall be deducted.