Does Phospherescent Chamber basically double the effectiveness of Mist-fueled recovery (making it 2 hp of healing per 2 cards returned from the trash) ? It looks that way to me, but not sure.
-awp
I think it does, as it says she regains 1 HP for each 2 cards, if it were using X then it'd only increase the single time.
From where I'm standing, that has basically the same text as Vicious Cyclone and other cards that are multiple attacks. I'd say your interpretation makes sense.
It does in fact make the healing 2 HP for every 2 cards, but note that this is SLIGHTLY different from 1 HP per card - she still needs an even number of cards to get the maximum benefit.