Short answer
Overtime drops when the schedule stops treating every gap as a surprise. List the shifts, roles, and days that run over most often. If the same pattern repeats, fix the plan. If the cause changes week to week, fix how you respond on the day.
This is not about cutting hours. It is about moving hours into the right place before the week starts, so the team covers demand on regular time instead of emergency overtime.
Separate planned overtime from emergency overtime
Track which shifts create overtime more than once
Move flexible tasks away from peak hours
Build a small absence buffer into high-risk shifts
Offer voluntary cover before overtime becomes mandatory