The following comments and/or suggestions, are made in an attempt to help the OP with his fuel issues, and are in no way meant to insult or offend ANYONE who commented on this post.
With that said, I will try to explain, and suggest what I think may be causing some, if not all of his issues.
Everyone will get different MPG depending on several variables, in altitude, how the bike is ridden, shield position, state of tune, brake issues etc.
MY personal bike gets 56-58 MPG (US) ridden on the roads I ride on, in the manner that I ride it, and the state of tune I keep it in.
Several folks who keep detailed records, and record every fill up, or use apps will point out that THEIR stats prove that its not possible, or that their bike(s) don't get that.
Perhaps, but my bike does, and several of the bikes I've worked on now also do etc.
So it is what it is, these are just my comments and opinions, again not meant to piss anyone off or offend them.
I've see the OP comment several times that the brakes were checked by pro's, and a guy who knew his stuff etc.
I've personally repaired so many bikes that Pro's have screwed up, or thought they knew what they were doing, that I've lost count.
My comment to this would be DON'T BELIEVE EVERYTHING YOU THINK.
Maybe your putting too much trust in the shop's, or your friends ST knowledge?
The OP keeps saying he was TOLD things were cleaned and checked etc.
I would question was it checked correctly?
Did someone really pull off the vacuum lines and check the tee? Then did they just push the old dried out lines back on, possibly causing vacuum leaks?
I've see several dealership hand customers back parts that didn't even belong on the model or brand bike that they worked on
I would love to see a picture of the T-stat that they gave back to him posted just to see what it really looks like.
The OP said these folks informed him that the brakes were in good working condition, and not the problem.
I wish I had a nickel for every time I heard that one.
The owner should try and find a forum member near him to assist him in checking his brake system, to just really rule that out.
I personally suspect that ONE of the contributing factors of his issues are probably in fact, brake issues, only because I find so many of them failed, and folks have no idea how bad it is when they ride in.
I don't care how anyone rides, or what position his shield is at, NO ST should get that kind of fuel mileage.
Running out of time here today, so I'll cut to the chase....
The four plugs I posted were two different brands (NGK & ND DENSO), and two different styles (STANDARD & IRIDIUM).
One plug was used I pulled from a bike on the lift, and the other three are new stock.
Anyone notice anything different from HIS picture and Mine?
Perhaps he should check the NGK website on how to spot knock off plugs etc.
Most, if not all of the INCORRECT fitment plugs, whether knock off or not, should be similar.
Look at the shoulder(s) on the correct fitment plugs, then look at the threads on the plug the OP is holding!
No shoulder, and way too many threads.
I'm guessing he has a few things going on, which may include brakes, T-stat, but absolutely those are not the correct plugs for that engine!
Borrow a bore scope and inspect the top of the pistons.