Expect the system to drift, and check it monthly

Every commercial system decays: people leave, jobs change, and someone quietly goes back to the spreadsheet they had before. Treat that as a signal rather than a discipline problem, because a step people route around is usually a step built wrong, and fix the step rather than police the person. A monthly half hour spent reading what the system actually produced against what the month actually contained catches the drift while it is one conversation instead of a reconstruction.