casting frequencies

sorcs never cast poly morph.. or on the very very very rare occasion. I skimmed through the common.ai and human.ai but i didnt see anything on ablities, just build order stuff. Is there anything that i can do to change this?

edit:
n/m after some searching it seems that computer micro management is hard coded... shucks

Sorcs do cast polymorph quite often when they have enough mana and researched master. The second point is the problem with the original melee AI. It nearly never reaches that point.
If you want to see it play with AMAI. When the human goes mass casters he sometimes turns the entire enemy army into sheep.