The retirement allowance (i) of any member retiring for disability from a cause compensable under the Virginia Workers’ Compensation Act (§ 65.2-100 et seq.) or (ii) of any surviving spouse, minor child, or parent, eligible to receive a benefit as a result of the death of a member from a cause compensable under the Virginia Workers’ Compensation Act, who elects to receive a lump-sum settlement in lieu of periodic payments for disability or death compensable under the Virginia Workers’ Compensation Act shall be adjusted by an amount determined by dividing the workers’ compensation benefit which such person would have received had the lump-sum settlement not been consummated, into the settlement actually accepted by the member, surviving spouse, child, or parent.