The current spreadsheet template has 3 different financial mods..
GMBeta is a simplified version of the GMExcel tool, meant to make a more immersive single-player experience, but without lots of input. It randomizes some aspects of things to make the finances of managing a team a bit harder than just using the in-game setup, but it easy to manage as a solo player not needing to input all of the league's teams to make it work well.
GMExcel combines the essence of past versions of the tool into a modern version that actually borrows from the FOBL system because I like aspects of it. It still works for a single player -- doesn't require the whole league input -- but does need more information. It also gives you credit for more success in ways the simplified version doesn't. I'm still working out the kinks of the structure, but...it's a worthy successor to the past version of my financial mods.
The FOBL one is from the old FOBL league that used to exist in the early part of the 21st century, it was weird because we had our own financial system that existed outside of OOTP (the finances were essentially a closed system) a hard salary cap and rules that essentally made it a parity-driven exercise.
We never had a spreadsheet that calculated the financial system though, until now.