The Seamaster 600 / Proplof has some particularities that requires our attention.
First, the monocoque case (I don't have an exploded view here) to be opened requires the removal of the bezel, glass (that may crack - is mineral glass) and several rings and gaskets until one can reach the movement (to do any maintenance).
Those 70's gaskets, made of rubber, or they melt or they crack, leaving material that can contaminate the movement.
Those old dial / lume also leave contaminants that may affect the proper movement operation.
That is the reason why any professional organization insists on a full maintenance every time they open a vintage watch because the simple opening of the case (not that simple for the Seamaster 600) can spread contaminants all over the movement.
About the service cost, Omega (and other manufacturers) have a detailed price table for maintenance on their web site.
No surprises there. To maintain a vintage watch, the price is higher than a modern one.
Thanks,
Nilo