The spreadsheet has been developed to strike a balance between fair playing time for all, and least disruption through minimal substitutions.
An example -
Squad of 12 playing 7v7 with a dedicated goalkeeper -
Goalkeeper - Full Match
Outfield players will get 2 quarters on the pitch, with 4 players getting 2.5 quarters.
Only 2 substitutions have to be made to achieve this, allowing your players time to form partnerships during the match, and gives you more time to watch, enjoy, and coach!