In the SafePay file there is no field to include a 'Rule-Off Date'. The only way to populate a date to show end of the current month is to set that field as TEXT and hard-code in the appropriate month-end date. This would require this client to manually update that 'Rule-Off Date' at the start of each month.
Having this functionality available in the SafePay file as a date option would be more efficient than manually having to change the file before sending to the bank. The 'Rule-Off Date' was required by the bank.