Is there a reason a CP cutter wouldn't work for MP? Just curious, I've only made MP a few times and I've been mostly using individual molds. I did cut some large bars into guest bars with my knife, that worked well.
I made a loaf of melt and pour soap and used my soap cutter from Bud Haffner. It worked, but I was very careful on how much pressure I put on the wires while cutting it as soon as possible. All in all... not advisable.