Thruxton 2017 Thruxton Idle Setting

I have a 2017 Thruxton that I've owned from new. I bought the Dealertool for my bike, and have used it several times. Most recently to balance the throttle bodies. Really love it! One issue I've been dealing with, and have not found an acceptable answer to, is this. High idle speeds. When the bike was new, on cold start it would idle at about 2,000 RPM for a short while, then drift back down to about 1,000 RPM once warmed up. Now on cold start it races right up to 3,000 rpm, and stays there for a long time. As the bike warms up, it eventually settles at 1,400 RPM. If I twist the throttle hard against the idle stop, the RPM drops to 1,000 RPM. When I let go of the throttle, it climbs backup to 1,400 RPM. I cannot adjust it with Dealertool. Is there a mechanical adjustment I can make somewhere to fix this? Can't seem to find any info out there, and I don't want to ride almost 200 miles to a dealer to be charged a bunch of money for someone with 42 years of jet aircraft maintenance like me can do if only given the proper procedure. Not to sound harsh, but no, there are no throttle cables, fuel mixture screws, or anything lie from the old days of carburetors on this bike. I say that, because everyone I've talked to about this that say they have an idea what is wrong starts talking about those things. I'm going to go out on a limb here and guess that there is something not right inside the twist grip as from what I've read, there is supposed to be about 4MM of slack in the throttle grip from the factory. I have no slack. I think the grip at idle may be pulled back just enough to cause a 1,400 RPM idle because of the lack of slack. Looking forward to hearing advice from those that know. Thanks.