Keep it simple
I have an excel spreadsheet where each row is a day. I log my instrument flight time in column L in decimal hours. eg. 1.2, 0.0, 2.3, 1.4, 0.0, 2.5
Column M is simply =SUM(L1:L89), =SUM(L2:L90), =SUM(L3:L91) etc.
Column M will read, 1.2, 1.2, 3.5, 4.9, 4.9, 7.4
There is no need to worry about a rolling total like last 7, 30, and 365 day flight time totals as there is no need to subtract times.
You only need to know how many hours you have logged in the last 90 days.
Works for me ...
Two Dogs