A. No insured institution shall borrow an aggregate amount exceeding one-half the amount paid in and credited on accounts, except that with prior approval of the deputy director, any such association may borrow without limitation on such terms and conditions as may be required by the lender. No action of an insured institution in obtaining funds through borrowing, in accordance with this section, shall be deemed a violation hereof if its aggregate borrowings exceed the limitation of this section because of a subsequent reduction in the amounts paid in and credited on accounts.

B. A debt incurred by the association in violation of this section is not invalid or illegal as to the rights of the lender.