After running for 24 hours now, I'm thinking it is a power setting. Voltage Level Offset seems to behave as it should now.
So after ~34 hours of mining with the new firmware (and adjusting voltage offsets) I can say w/ certainty that the new MM reduces the hashrate. Of the two machines I installed it on, both lost 1.5-2TH/s. I've rolled back to the old firmware and the machines are back at their normal 20TH/s. If I had the machines locally I would test their power consumption with the new firmware running. I'm wondering if the loss of ~1.5TH/s came with a decent reduction in current; can anyone with new firmware running test this and report their findings?