I haven't needed a spreadsheet
I haven't put my points on a SS. We have 525K points, 315K on 10/1 year and 1 EEY 210K and 1 EOY 210K both for 1/1 use year. Whenever I make a reservation WW takes out the soonest to expire first. The only time I run into trouble is if I cancel an earlier reservation. Then they go back with the original expiration date. Personally, I think having all my points on the same use year would be less flexible. When we bought our last contract ( I know, from the developer, how stupid, water under the bridge) they offered to change our 1st deed so that all were on the same year. We actually told them to go ahead and do it. BUt it never happened, and I have been grateful ever since.
Kathy