Magical Training is only acquired once. Also, you forgot to subtract 5% from the bonus sp for items due to the 1 bard level (18 Sorc + 1 FvS = 19/20 levels that give double, so 95% instead of 100% bonus).
I was doing my calculations off of the +23 (in-quest) modifier, since I was only interested in the theoretical maximum, not the quasi-sustainable maximum.