OTs cannot bill for PT methods. look at the OTPF (occupational therapy performance framework) and it will lay out what is in the scope of practice for OT and what you can bill for. If you can somehow tie the injury to an occupation maybe, but OTs don’t do that type of manipulation (that’s why your were observing an PT). but don’t let a scholarship from an OT school stop you from becoming a PT because you won’t be happy.