Just had a thought: I've been working so many long hours, including while my boss was away, that, assuming he came back to check my timesheets, he may see this as an opportunity to finally ... well, let's say confront me about my hours.

I've come to the conclusion that I have to stay to complete the work.  Measures supposedly were taken to lighten the workload, but with one important but small (when it comes to the workload) difference, it hasn't changed at all.  The main issue, to me, remains that there isn't a second person helping out day after day to take stuff off my plate.  Without that, everything falls on me to do.  That's why I stay late and accrue overtime.  If I don't and leave early, all the stuff I left will be waiting for me the next day, and you can add that to all the other stuff that comes in that next day.  The work accumulates, and if there's only one person doing it, well, that person is doing it.  So, if I don't stay late and do it all that day, I'll have to stay even later and do it all the next day.

I hope my boss understands that, but because my co-workers are apparently superhuman beings who get all their stuff done on time, I am becoming more and more confident he is going to come down on me -- either set new rules, set an ultimatum about ... something, or just yell at me like he has before.  And all because I'm just doing my job to the best of my ability, huh.