A change in monster code will result in yon average monsters
casting the single target damage spells (such as magic missile
or golden arrow) with a much wider variety. They should not be
casting more, however, just that they now may choose almost
whichever type instead of the old, rather limited ones.
There may or may not be a possibility that the damage caused
by these spells (as cast by a monster) might or might not have
undergone a slight or greater change for better or worse.
Report possible bugs or tune-related problems directly to me,
report to Pahvi instead if you just feel lonely and need a friend.