Tootee, What I aimed to rebut was the assumption that upgrading armour is bad against armour piercing striker because when you get an additional armour, you are actually giving better bonus to the armour piercing striker." Since the armour piercing striker gets -1/2 combat factor or kill chance if defender upgrades it armour, the former assumption isn't true.

Thanks for the clarification yuuki, now it's either no gain of combat factor from armour piercing striker or -1 gain. However, this makes upgrading a little bit tricky (considering armour piercing striker only) suppose at the 1st upgrade we get an odd armour value, striker gets -1 so it serves the purpose, at the 2nd upgrade we will get the striker to have same combat factor as before, so we waste the 35 % upgrade cost for nothing.

My current assumption is this: In order to minimize the bonuses of the armour piercing striker, defender has to upgrade to +2 armour if his current armour has an odd value. and to +1 or +3 only if his current armour has an even value. Is this correct ? Not something that you need to consider greatly since not all striker is armour piercing, but for all those ppl who love being tedious in troop selection I think this is important hehe... .

Fast: Well, since you can't see how many armour upgrade a defender has, my answer to you is dont bother, just like kocmoc or magyar think about it, "FEEL IT" dont be too mechanical . In this case I kinda agree with them.