I’ve been retired for some years now, so I am not up to date on the ever changing DOL exempt from overtime rules. That said, I think employers abuse the system. I moved from an hourly position to a salaried position at one point in my career. When I made the change, I was still declaring my time off in 15 minute increments. A few years later, the HR person said I only had to declare absences of 4 hours or more.
Our pay periods are 2 weeks. If you work 50 hours in week one, you can put 10 hours into a "personal time bank" and submit 40 hours. The 10 hours can be applied to week two on the way to 40 hours. The PTB feature hasn't been of much use to me as most weeks exceed 40 hours so there is no point in using PTB.