Are those range values right? The 912iS is a lot more fuel efficient than the ULS. The POH says 493/368 nm and 547/440 nm for the iS/ULS respectively.
That question came up awhile back in the RV-12 forum. IIRC, 'rvbuilder2002' (Scott M.) addressed it and explained it. Maybe he or an RV-12 folk can point us to the post with the explanation.
EDIT: This is the thread that discusses the range numbers:
Yes, I recall that thread. What I was querying was the figures in post #68 that show very little difference in range in between the iS and ULS. That doesn't look right. Maybe a typo?