Board Thread:Plants vs. Zombies Heroes/@comment-27101994-20170405125546/@comment-25089892-20170409113130

From what it looks like, opening a multipack is treated by game as opening 10 normal premium packs + 1 "Super Rare Pack" that offers you 3 guaranteed Uncommons, 1 Rare, 1  Super-Rare, and 90% chance for another Uncommon or a Legendary.