I have a 1920's cushion case watch, that is cosmetically in great condition but it loses about 5-10 minutes per day. I'm looking to get it serviced, and I know a few watchmakers in the area. For a watch this old, would it cost more to service than a modern watch? Is it more complicated? I know it's different with every watchmaker but in your experience is a watch over 80 years old considerably more expensive to service than a watch that's 10-20 years old?