I've worked two peaks, 2019 and 2020. They say in the hiring literature that it's flexible. However it really depends on the center. What I saw locally was the supervisors wanting you to work as much as you can. Frowning on flexible or people only wanting few hours. As PVD or SPVD or SPVPD they keep changing the acronyms. lol However you are capped at 60 hours per week. At least that's what they did last year. I was out last peak delivering until around 10 pm. Which is rough on both driver and customer. And a few times even later than that. Picking up straggler packages which were misplaced and had to go out. Who wants their door bell rang at 10 pm at night? They did make some changes at local Peak Pop-Up Seasonal Center. They had us coming in at around 7 - 8 am and leaving before the package car drivers. Because we were delivering so late. However we were having to take photos of the package labels and or writing them down when delivering because the packages had not even migrated to the system. So working 3 pm is really getting toward end of day for some. One thing they might do is give you straggler packages, and have you deliver those. Or give you a very small route. The thing to keep in mind is the Supervisors stare at screens all day long. And want those packages out ASAP so they are not there at 9 - 10 pm working in the office. So starting at 3 pm is not really standard. At least in what I saw over the two peaks. PVD is a Union Job in some states. Such as California.