If any benefit is payable by this system to the estate of a deceased person, and the estate would not be probated if no amount were due from this system, but there is no surviving person in any of the groups specified in Section 21493 or 21494, or if no beneficiary can be found by the board, the board may in its discretion pay expenses of the disposition of the body as evidenced by itemized statements or documents the board may require. Payment may not exceed the amount payable under this system to the estate or beneficiary. Payment so made is a full discharge of the board and system for the amount so paid.