You must be new to shopping?
You were informed correctly by the scheduler. It IS up to you. The ones that you name are MSCs. Scheduling companies are NOT MSCs and do not pay you. So whenever you take a job assigned by KSS or Coast-to-Coast, for instance, be sure to find out who THEIR client is, i.e., who the MSC is. You are running a business now. Independent schedulers, also do not pay, so find out who they are are scheduling for (the MSC). It helps to put the assignment on your calendar as "Mighty Bank" for Informa, scheduled by xyz scheduling.