I should have realized that Rick Robinson's "Spring Style" program has a lot of "hacks"

I have been studying Rick Robinson's "Spring Style" program, and so far, I have been disappointed to see that it is filled with "hacks" that only "sort of" give the right numbers. Partly, the scope of what he is doing is larger than I intend to do. He is trying to cover 1860 to 1945, while I am concentrating on 1905 to 1927 (although it will pertain to the 1900 to 1945 range). I am going to adapt my Excel spreadsheet calculations rather than doing "hacks", as much as possible.