Yes it's the weight of money that eventually determines the final price, and as Twobets said, if a horse wins at $1.10 by a head then it was at the correct price, if it wins by 5 len. then it was overs, even at that price and if it lost, then it was unders.

But we don't know that until the finish!

This of course assuming that every horse had a fair chance in running, and nothing untoward was going on.