It's hard to answer someone else's question about that sort of thing. Personally, I'd go with the fitting. I would think a .25* difference would give results that were pretty slight, but maybe your average results according to the computer suggested it.

That said, I've been fitted for irons, but never for a driver. My attempts to adjust various drivers between 7.5* up to 12* never proved much to me. At 12*, I lose distance. At 7.5* I lose control, but everywhere in between just seems the same, the trajectory, the distance, the ability to move it both ways... Nothing between 9* up to 11.5* ever seemed to matter.

I would suggest going to a Titleist Thursday and trying both to see what numbers you get on Trackman (especially trying the different scenarios you mention)!

If you have a tendency to impart side spin on the ball in an unfavorable manner I'd stick with the fitting. .25* is small, but loft is your friend if you need it. Could be the difference between playable and unplayable, or having a line to the hole and having to punch out if you are a spinner.

Follow the fitting.

Follow fitting. Still can go up and down, but if I am fitted to 10.5, I would not buy 9,5 and adjust, as you slightly open the face by going up with degrees.