Ptf, transferring

Just started working in the Chicagoland area and I’ve been a ptf city carrier for around 6 months. However, most ptfs are only averaging 8 hours unless you have a hold down on a route, which it’s 9-10 hr a day. The problem is that there aren’t many regulars on vacation right now so there aren’t any routes to bid on until next month, which will be a hood down for 2 weeks. However, majority of the post offices in the surrounding neighborhoods are working their ptfs 11-12 hour shifts regularly. I want those hours, I’m fine with the constant ot. I was reading it isn’t possible to transfer until I’ve been here for 12-18 months?? Is it possible to quit and go talk to a post master at another post office and get hired directly through there? I know sometimes regulars receive less hours than ptfs/ccas so I want to milk the money cow while I Can thanks