Merely removing one claim would be sufficient to avoid their patent. It gets tricky if you "change" a claim, because then you have to consider the substantiality of that change. For example, moving the "point escrow" of claim 9 would be sufficient to avoid their entire patent, but you'd likely be staring down the barrel of the dirtbag attorney they hire to drag you through the mud in an expensive federal court case, hoping you'll just opt for a licensing agreement. It is what it is.