If it’s a new SM she likely is still learning scheduling. I would bring this up to her so she can improve, or she’ll give you her reasoning. Regardless there’s no reason why closers should be leaving 3 hours after close unless it’s clean play.

How many people are being scheduled for peak?

I am on my second external hire SM and they've both been...not good. My current one has only hired two people after losing 9 partners in 6 weeks. I gave him the benefit of the doubt for the 6 weeks hes been with us but working so understaffed has caused me nothing but stress. So I asked to transfer back to my old store who has a SM who is a seasoned partner and I've worked with before.

Hope your situation gets better. If not, I hope you can transfer to a better store!