GMT Precision

[Quicksilver]

Sorry to start yet another thread about accuracy....but here we go.

The issue is one of precision rather than accuracy. My 2003 GMT was very precise until it went in for a service last year when it came out behaving quite erratically. It went back into Rolex who "observed" it for a week or two and then declared that they were happy with it. They set it to run at + 2 but it soon ran at -3. I took it in to be regulated and they set it at +2 again but it started running at + 6.5. But it seemed to be precise at least, running pretty much at about +6.5 daily.

A few weeks ago I decided to check on its progress by measuring it weekly.

Week 1 - it gained 3.5 seconds (an average of + 0.5 per day).
Week 2 - it gained 18.5 seconds (an average of + 2.64 per day).
Week 3 - it gained 36 seconds (an average of + 5.14 per day).

My wearing patterns are the same every day and I lay the watch crown up every night.

I am now going to try daily measurements.

That's quite a variation. It's only a 2003 model and its just been serviced. Is it to much to ask that it should be precise and show pretty much the same degree of variation daily? I know it's running within COSC but the weekly fluctuations are concerning.

Or am I being over fussy?

Also, I wonder what could cause these fluctuations?