Time Adjustment

[Lex_Ordo]

Hello fellow watchaholics...

Tech question?

Watch is running slow. I would prefer the watch to gain time. I have had other Rolex watches that gained time and this is the first that consistently looses.

Reference 116710 Caliber 3186. I have had it into service previously, but unfortunately, it continues to loose time.
Would a a mainspring change be warranted or the balance wheel/balance spring combo?

I am leaning towards the balance wheel and spring, because the weight adjustment doesn't seem to be correcting the time loss. I placed the watch in several different positions, using a time grapher, and the +/- S/D varies which I expect. however some of the readings seem a bit too varied to be within chronometer specs.

Amplitude is a bit low, under 270 degrees, but the beat error is pretty even at 3ms.
Could the amplitude be the culprit?
Could the balance wheel be weighted incorrectly?
Is the hair/balance spring tension not tight enough?

I am going to bring the watch in for service, but I figured I'd ask the group too.