I was just reading something and I think that I may be missing it.
If you are trying to cast a quickened fireball defensibly, what would be the DC?
Would it be:
a) 15+(3*2) = 21 (as it was a 3rd level spell)
b) 15+(7*2) = 29 (as if it was a 7th level spell (the slot that it is now using).
TL/DR: Do Metamagic feats effect the Spell level for concentration checks?