[Gameplay] Valor miscalculating with arpen

Valor does calculate armor penetration, but does not account for being unable to reduce an enemies armor below 0. This comes into play when Valor looks for a target you can only one-shot with a mark currently.

This means that earlygame when Valor looks to help you last-hit by looking for targets you can't one-shot yet, but with a mark you can, you will come a tiny bit of damage short. This leads to missed last-hits. (Valor thinks you can reduce the minions armor to negative amounts and calculates using that)

Repro: Take heavy flat arpen runes, low flat ad in runes/masteries (lower ad makes this easier) Go to a lane, wait for Valor to mark a minion to help you last-hit (don't attack anything or Valor will automatically mark the target you attacked, going on cooldown) Hit the marked minion, notice that your attack deals less damage than the minions health was at when Valor marked it.

Just a minor bug that one is able to work around, but bothersome.