Ok, well If your pool or mining software is showing the correct values, I shouldn't worry too much, as in my experience with blades that is the more accurate. I assume you have adequate cooling? I recently added a 20cm fan to my set up and the config pages showed a 400 mh jump in both blades.
I understand your concerns, but as I said, the config pages are inaccurate to say the least. Sounds like they are both hashing ok to me.
Well, my non-contact laser thermometer says the hottest point in either blade is about 40 degrees C. That's the column of chips that is furthest from the 110 cfm fan, on the front board (no air channel in front of it, so the far end gets less flow). Both heatsinks register at 25-30 deg C (lower nearest the fan).
I guess I'll just be satisfied with the hashing reported by BitMinter. Sure seems pathetic to pay $500/board, and not have the firmware be even vaguely accurate. You'd think that the manufacturer would open source the firmware, if only to get more quality in his next round of boards, more quickly. I'd sure spend the time to buff up the firmware if they did!