I don't have a problem paying for my own screenings but I do expect the MSC to compensate at a higher level than they would for a shop not requiring special qualifications. Just like I expect to receive more for a shop that requires I have a late model luxury car than one that doesn't care what I drive.
Just like any job or consultancy, the higher the demands by the client/MSC, the better the employee/consultant expects to be compensated.