If you go to a new center, you will need a new prescription for the therapy, and can ask the doctor to write it for your legs and hands. If you go back to the same place, the doctor can send an additional script there. You will be evaluated/reevaluated, and they will come up with a new plan. If the facility doesn't offer OT, and they think you need it, they can refer you out.

Being seen for two different problems doesn't mean going to therapy four times a week.