When we switched from MT 4s to MT 10s there was improvement, but still some weird colors, still not as well formed, but better than before.
DS' situation was a little unique in that the reason he wasn't gaining weight was because he had surgical adhesions from his surgery as a newborn due to meconium illeus. The surgeon last summer said he looked like a child who'd never had enzymes because the adhesions slowed down his digestive process so much, his enzymes didn't get to where they were supposed to be. We also had him on 5 MT 10s.
After he got things resolved last summer we bumped up his enzymes to 7 MT10s and he's been having normal brown, well formed stools. "Sinkers not Stinkers (floaters)".
He has been on Pancreacarb 4s and 8s which worked well for him, too. Unfortunately, the FDA hasn't approved the new packaging yet.