Rolex 3186 behavior

[AID_]

Hello Gentlemen! I have a pretty specific question about Cal 3186 and hope that someone with experience with this movement can answer it. I have to disclose that I am a hobbyist watchmaker with a fair amount of experience, but mostly working with inexpensive vintage watches and some contemporary ETA. The only Rolex a serviced in and out was Cal 1570. I have been inside 3135 a few times, but only for a quick adjustment. Thus - I have very little experience with Rolex movements.

Anyway, I just bought an "almost new" GMT Master II with 3186. The watch was originally sold six months ago and only warn a few times, so it's practically new. I have this watch for 3-4 days it runs perfectly with only 4 or 5 seconds positional error in four main positions. When fully would it shows an amplitude around 300-310. But within a couple of minutes amplitude drops to 270-280. The amplitude is stable from there on.

From my experience with ETA once the fully wound movement settles amplitude is usually 290-300. But on this Rolex it's somewhat lower. I would say almost on the border of normal. Unless Rolex has different specifications for this caliber. Does anyone have an opinion on this matter?

Thanks.

P.S. I assume lift angle is 52' for this movement. If not, it throws all my numbers out of the window