Where a disability beneficiary is restored to membership in connection with a return to active service, the net amount of the contribution balance standing to the credit of the member at the time of retirement, after reduction for the amount of any outstanding loan, shall be reinstated. The amount of the loan outstanding at the time of the retirement shall not be reinstated. Upon subsequent superannuation or service retirement, the benefits otherwise payable shall be reduced by the original amount offset at the time of the previous retirement with respect to an outstanding loan balance pursuant to section 517-c of the Retirement and Social Security Law plus any additional offset calculated under such section 517-c with respect to outstanding loans taken during the restored membership.