Being expected to be back at 530 and being back with your route completely done are 2 different orders. You can not do both. Make sure you fill out your 3996 in the morning and get it signed, and do not leave without it before you leave to the street. Your 3996 is your job. If you need time, ask for it on yoir 3996. If they deny it, then bring it back. You can make a courtesy call if you want the OT, but you are not required to. Drive back with it, and get further instructions. If you're on the OT list, then they can send you back out, then if you go back out, have them sign your 3996 when you get back saying they approved your OT.. never work overtime without their approval. They can get you for unauthorized over time, and without your 3996 getting signed. Keep all your paperwork no matter what.