No bank subject to examination by the department of finance may cause to be performed, by contract or otherwise, any bank services for itself, whether on or off its premises, unless assurances satisfactory to the department of finance are furnished to such department by both the bank and the party performing such services that the performance thereof for any such bank will be subject to regulation and examination by the department of finance to the same extent as if such services were being performed by the bank itself on its own premises.