The proprietor must enter the employer identification number (EIN) assigned to it by the Internal Revenue Service on each form TTB F 5000.24, Excise Tax Return, filed with TTB. Failure to enter the assigned EIN on TTB F 5000.24, may result in a $50.00 penalty for each occurrence as specified in Sec. 70.113 of this chapter. (26 U.S.C. 6109, 6723)