What do you mean by "expert tier"? I must be missing something here.
If you were playing the Dragon, it sounds like you would have only received 2 green check marks. The extra 2 from "expert tier" I don't see where you are getting those.
If you have the rulebook that came with the game you don't have the "Challenge tiers", download the v1.1 from Onedungeondeck site
The updated rulebook includes a new section on page 23 called Challenge Tiers. These allow you to reduce the difficulty of One Deck Dungeon. Expert Mode is the rules as originally written. Standard gives you one free card as XP to start each game, and Novice lets you start each game at experience level 2. In addition, Expert gives you two extra campaign checkmarks per game, and Standard gives you one.