The attorney or other parties may advance to a domestic reciprocal insurer, upon reasonable terms, such funds as it may require, from time to time, in its operations. Sums so advanced shall not be treated as a liability of the insurer and, except upon liquidation of the insurer, shall not be withdrawn or repaid except out of the insurer’s realized earned surplus in excess of its minimum required surplus. No such withdrawal or repayment shall be made without the advance approval of the commissioner. This section does not apply to bank loans or to other loans made upon security.