The Comptroller, with the approval of the State Treasurer, may provide by rule and regulation for the transfer of moneys held by the State Treasurer, whether in or outside the public treasury. Such transfer may be within the same fund or between funds and may be made without the use of the voucher-warrant system. However, documentation of approval of the transfer by the Comptroller, and the Treasurer shall be retained by the Comptroller. The Comptroller, under this Section, shall make a transfer only where the transaction is otherwise pursuant to law and authorized. As used in this Section, a “transfer” is limited to a transaction involving only a State agency or between State agencies exclusively.