Um maybe 11 or 10 13 seems high
Here's a suggestion that i think we all should try if we're unsure about the cost of something in a few short steps:
1) Get several (a lot) of post-it notes or other small items to label as cards.
2) Once you've made all the cards, play a game with yourself/someone else.
3) After several tests, evaluate the current cost and make a change if necessary.
4) Repeat steps 2-3
Note: This does not work for Fallen Druid/Elf
The quanta amounts might be a bunch to keep track of, but if you go through with it, this should get you some good results.
Perhaps you will remember to check the QI and see if it's the problem instead of the cost.
Speaking of QI, now to go test that theory on my own decks.