5vs5 rating - what's achieveable?

At 1850 our team went to the point where we would gain 3-4 rating for winning a game, and 18-20 for loosing, so random disconnects on loading screen combined with very able opponents became too much of a risk to continue. On average we have had discs on 10% of the games so far.
I'm thinking the best teams are at 1900-1920, am I way off? 5vs5 top ratings seem to lie a lot lower than 2vs2 and 3vs3, yes?