229-16(c)(3) from the BOL Reg CC page:
(3) Overdraft and returned check fees. A depositary bank that extends the time when funds will be available for withdrawal on a case- by-case basis and does not furnish the depositor with written notice at the time of deposit shall not assess any fees for any subsequent overdrafts (including use of a line of credit) or return of checks or other debits to the account, if--
(i) The overdraft or return of the check or other debit would not have occurred except for the fact that the deposited funds were delayed under paragraph (c)(1) of this section; and
(ii) The deposited check was paid by the paying bank. Notwithstanding the foregoing, the depositary bank may assess an overdraft or returned check fee if it includes a notice concerning overdraft and returned check fees with the notice required in paragraph (c)(2) of this section and, when required, refunds any such fees upon the request of the customer. The notice must state that the customer may be entitled to a refund of overdraft or returned check fees that are assessed if the check subject to the delay is paid and how to obtain a refund.