Shoots, I made a mistake.

I assumed the buy-back period NAV/U -2% for the buy-back price instead of the daily NAV/U -2%. So now I understand period NAV/U is just for the period's ask/sell price, not the buy-back basis.

So period's NAV/U+3% for SELL and daily's NAV/U-2% for BUY-BACK.

Well that changes EVERYTHING in my spreadsheet.

Okay a test then. If the daily NAV/U rises substantially above the period NAV/U, would you change the price of the B.EXCH to the higher NAV/U + 3%? Why wouldn't the sell price be based on the daily and not the period's as it is now?