Hi,
Maybe if you load a (spoilt) film, you may find that the shutter speed will coincide with the meter reading: the SPD cells looks at the film. If there is no film inside the camera, it will see the black pressure plate, and that will change the shutter speed considerably (it's a "live"system), compared to the reading before you release the shutter.
As for the switch, maybe a tiny dop of lighterfluid will remove the grime.
Cheers,
Jan