RB motors have some of, if not the highest tolerances between the piston and sleeve of any engine. Or, you could say they come from the factory with the tightest pinch... from my limited experience anyway.

Because of this, I like to up the temperature of the heat cycle to 220. I believe that little bit of extra expansion is important so as to not cause extra wear on the sleeve. With a tighter than average pinch, it seems logical that more sleeve expansion would be necessary to prevent the piston from scraping as much on the sleeve. I'm guessing this would also have the added benefit of being a bit easier on the conrod.

180 is certainly not too high.