or wikia is wrong?
Probably critters were changed, may be molerats became more evil and now have 8 AG so 8 AC, so you have on 2% less than it should be. I can't remember how many hexes they are walking, because fighting them in TB was session ago, so can't remember how much AP they have.
It's easy to check. Just go into TB, and check %to hit with bare hands, if you have not high %unarmed. Then just see difference of %to hit and %skill, and you'll see thier AC.
Or, you can watch how many hexes they walk in TB and see thier AP, so you'll know ~number of AG +/- 1.
After that, when you'll see that they have not 8 AC, you may say that formula is wrong and it'll be a bug!
Edit:
Tested, molerat has 6 AC.
Then formula isn't right, or you have on 2% more skill.
Or there's something else that not mentioned in formula that deduct 2%.