Form 6088 for frozen plan

If the plan frozen benefits in 2003 and its termination date is in 2021, is the compensation entered in column (e) compensation to 2021 or 2003.  If the former, do you need a separate schedule for plan compensation to 2003?

The instructions are clear - they want hi-3 average for a DBP (checking 415 limit) and if the benefit is based on something different then you need to attach a separate schedule that shows the compensation upon which the benefit is based (so they can spot-check that).