About monster attack/defense/HP "IV"s
Every monster in MHST has different stats, they were determined by values somewhat similar to pokemon. I'll call them IVs. IVs are different from the stat boost medicine in game. No matter what the IVs are, each monster can consume at most 10 medicines.
I don't know the exact algorithm yet, however:
The HP IV is at offset 0xD8
Atk IV is 0xD9
Defense IV is 0xDA
I set all three of those to 0xFF and I was able to get my black diablos lv99 (hacked already) to 9 skill slots with a ridiculous 1706 attack + 999 HP... I tried saving and reloading, battling, putting back to box(Not sure about leveling up, didn't test since it's lv99)... and it does not change... So yeah... this game's severely broken already by this point.
However, the defense decreased by 3 even though the defense value was 0xFF. Not sure exactly how those values cooperate with each other.
EDIT:
Tried on my lv1 dinovaldo. After battle and lvl up, the HP and the Defense didn't seem to be affected. However its attack bumped up to 2600+. I'm pretty lost right now. Not sure about the limit of IVs and the algorithm..