Yes, you can clock out before schedule but it will show up on your attendance report if it meets the threshold.
The "attendance report" logs TMs who clock in 7-8 minutes or more late (LATE), TMs who clock out 6 minutes or more early (LEFT EARLY), and TMs who clock out 6 minutes or more past schedule (WORK PAST SCHEDULE). It also logs CO and NCNS. The "CAPS" represent the title they are given in the report.
An ETL can hold any of those against you but you really don't have to worry about WORK PAST SCHEDULE at the TM level. Managing payroll is a TL/ETL problem, not a TMs. If you WPS then it is up to the TL/ETL to make sure TMs clock out on time. LPDAs will vibrate when TMs need to clock out if logged in as the LOD so they should know who needs to clock out (if they are logged in as LOD).
I held my TMs accountable for CO, NCNS, and LATE in excess of 15 mins. However, only if there is a pattern. Shit happens so I apply that to attendance issues. My only advice is to avoid overtime. That is a report HR and the STL follow up on. Some stores are more strict about OT than others. I had TMs hit OT at least once a month. It was more of a task for me to prevent it than the TMs responsibility. I was forced to "Coach" them but it was just an informal "Hey you hit overtime, let's do our best to prevent that in the future." Then we finished with a wink and a high five.