[Meglobob]

Not cast this spell but does lvl of casting mage have anything to do with it? A lvl 7D mage, casting pale riders gets 33 pale riders, +13 more than normal. Anywhere in the manual you see a + sign means more effects for a higher lvl than needed to cast mage.

I bet casting it in winter is better than in summer (or possibly vice versa in this case), Illwinter seem to like influencing alot of effects by seasons.

Casting some spells with different scales/seasons can result in some unusual results now and again.