Sorry you were right; please revoke my math card. I multiplied mana troop bonus instead of adding it.
It is 11 tiles.
Level 5 mana, three tiles at +1, +2, +6 did not charge
Total = 3*(1.07+0.05)+3*(1.07+0.10)+3*(1.07+0.30) = 10.98 tiles
I have one that does charge at 11.01 but yours at 11 trumps that.