Amounts advanced or transferred in accordance with Sections 11257 and 11258 shall be available for expenditure for the same period and purpose as the appropriation from which the advance or transfer is made. All or any portion of the amounts so advanced or transferred may be returned by transfer by the State Controller to the fund or appropriation from which originally advanced or transferred under Sections 11257 and 11258; provided, that upon final determination of the charges made or to be made under this article the unexpended balance of the amount advanced or transferred shall be returned to said fund or appropriation.