Thank you for this suggestion.
However it is my belief that a correctly defined "Date Interval Code" should take care of the backdating for us. I don't want users changing anything but Reference Date. When setting up the Date Interval Codes, I thought I detected some difference between the "Period" setting and the "Month" setting. I will be doing more work on this shortly, but had hoped someone here would have sorted this out already and could advise. If anyone can add to the above, most grateful. George