Couple different factors .. it's like transitioning from a pig to a 2+1 longboard. Different aspects for different boards, considering the Sims is meant to be ridden as a twin and clunky I'd imagine there would be the first difference. Thruster to twin, unless you're riding performance twins.. secondly paddling speed, float, tail width of a mini simmons don't apply as well to a standard hi pro thruster. 

Justmy opinion usually riding logs and retros then getting on a performance board.

there's concave / rocker differences when going back to the performance board.

All in all if you are consistently riding different equipment you will adjust faster and get back into your flow