UP stacks up, so 2 UPs means 4 As (all of them).
PLease note that UP requires hitting, not winning combat/dealing dmg.
So if you play 3 agains troq's K you lose combat, yet you hit, so u get only the 15 dmgs from the throw, not the 7 for UP, and you can fetch the 2 aces.
Same for zane's K etc.
Also Joker prevents dmg, not the hit to be sucesful, that is why it keeps giving you aces