I can "see" your point,but he is a mender.He is able to cure a sick watch,and I 've seen DEAD and gone thingies, in his hands, getting new life.
Most of all he has no gains in telling me that a movement is cheap and dirty or gen,since I am not buying watches from him,because he is not selling.
His attitude is pure pro and he is charging peanuts for his services.
My knowledge in movement things are ZERO, as far as mechanics are the subject,therefore I have to rely on what he says. If he gets it wrong ,then I say wrong too. That simple