One other possibility is they missed something in the reconditioning of your Thorens - perhaps a tonearm bearing that is a bit worn, dirty or under-lubricated and has a bit more resistance toward the label area.
You might check if a local dealer will let you demo a newer turntable. If the problem goes away with the new model then you've clearly established the Thorens needs a bit more work.
You might check if a local dealer will let you demo a newer turntable. If the problem goes away with the new model then you've clearly established the Thorens needs a bit more work.