So when I fight against the sorcerer kings lieutenants the fight has generally gone in one of two ways.

Either they try to daze a few units, then don't do anything too damaging and I defeat them easily. This is what happened in my first two games.

One my third game Ive attacked them with a weaker army but still matching the combat strength of the lieutenants. From my past experience I thought it would be a closer match but I would be able to come out ahead with possibly some losses. Instead of what I expected, before I can even move the lieutenant gets off a few attacks and then casts horrific wail and nearly wipes my entire group, making it nearly impossible to beat them.

The part that really confuses me is that in first two games where I won easily, I'm pretty sure that had they used horrific wail they still would have easily wiped my army.

Do units get some kind of drastic increase in spell resistance as they level up? How can I win if they decide to use horrific wail? It appears that I would need to equip every one in my army with multiple spell resistance items to even have a chance. How is it possible that in my first two games the fights were so easy?

All of these games were on normal difficulty.