Caution:

CC INTST does not provide correct computation of FTP or Interest if the pending transaction on IDRS is Unpostable (UP), Resequencing (RS), or Tape Edit Processing (TP). Use CC COMPA and CC COMPAF to obtain this information.

The penalty period for FTP (TC 276) is calculated from the date the penalty period begins (the Return Due Date) to the same date in each following month. TC 276 will not recompute if the payment is late and dated within the same monthly period as the 23C Date of the notice. If the return is due the 15th of the month, the penalty will not recompute until the 15th of the month after the 23C Date of the notice.