Necro Pets - Level 1 spell vs Level 4 spell

[Messianic]

I noticed my level 1 necro pet hit consistently for 8, whereas my level 4 pet hit for 7 consistently (obviously had more hp and more AC based on what other mobs were able to do). It made 1-4 really easy...But shouldn't the level 4 pet hit harder than the level 1 pet?

Am I missing something? I looked through a few pages in the bugs section of the forums and didn't see anything related...