if it peaks at 850 you don't have a problem probably could get reduced one click to make it cooler, but peaking at 850 no problem it shouldn't hang there though.
I've found that engineers and engine shops all have a slightly different opinion. Some say hot (ish) start means start is faster meaning less thermal stress on the engine. Some say high start peaks torch the back end over time meaning that when you do your hsi you will probably need new 3 or 4 wheels. Most of our starts peak about 810 think it's a happy medium. Not saying that is 100% right though.!
Remember magic number is 927 deg c get beyond that your in for some serious $'s