just got mine done at the stealership about 2 weeks ago. I have the prepaid maintenance though. I didn't have to pay a dime this time. But what they had on the paper invoice for my record was: sparkplugs, airfilter, oil & filter change, chain check and adjustment (which I know they did because it went in tighter than it should be and came back looser), and the valve adjustment. 5.5 hours listed labor at $70/hour = about $380 + parts about $505 total if I didn't have the prepaid. So if you just want the valve adjustment and only that I was say that Busahaya is within range.
I know that they teared off both side fairings (I could tell from the gap in the inner fairings afterwards that wasn't there when I bought it in). I believe it's quite a bit of work for them. 4 hours worth??? Maybe not with a experience tech. But that maybe the industry "Mitchell" book rating.
I know I had to leave it with them overnight because the valve adjustment had to be done "stone" cold.
I did notice a slight difference after I got it back in that the valve tapping noise at idle was reduced for me to not really hear it anymore. Word of advice is to see what the Mom & Pop shop will charge to do it. Just get a receipt to prove that it was done for you record.