I think there is a long and confusing history behind this. Once upon a time, there was a bug/feature that resulted in both the trim and the heading adjust moving at 10x speed. For heading adjust, this was a disaster but some people actually liked the trim this way. When the fix was put in (around about SU3, I think) it removed the 10x multiplier for both the heading and trim adjust. People were thrilled with the fix for the heading but many found the trim adjust to be painfully, painfully slow.
Many people wanted the 10x multiplier added back for the trim adjust but I personally saw this as a horrible way to fix it. If you do a 10x multiplier then your digital trim (button presses, even if they come from a wheel, like on the Bravo) will move 10x with every step. You completely lose any ability to make fine adjustments.
For that problem, of needing an increase in speed but also to be able to keep the ability to do fine adjustments, I came up with a way to improve it using freeware apps: [Video Tutorial] Fix your Digital Trim Wheel (Bravo, Logitech, Desktop Aviator, etc.) in-game speed AND precision using freeware
My hope was that when Asobo addressed the issue they would NOT just put back the 10x multiplier that many users were asking for. I guess they did just put back the 10x multiplier. I wish they could have done something like I did, with slow movements of the trim adjust giving small changes and fast movements giving bigger changes, but I can see where many users would also call this a bug.
I don’t know what the right fix is but with the 10x multiplier apparently put back in I don’t see any way to make fine adjustments.