I was also wondering how Extra Spell works in regards to the Sublime Chord PrC and its odd spell progression. If such a character wanted to take the feat and learn a 3rd level sorcerer/wizard spell (at say, level 12 when he receives a feat), could he? Sublime Chords start off knowing 4th level spells from the bard list and sorcerer/wizard spell lists and gain spells of higher level as they progress, but the PrC says nothing about whether or not they could learn spells of lower level. By the rules, it looks like it's not allowed, but common sense would say otherwise; just what is stopping a character from learning a lower level, and subsequently easier/weaker, spell in place of one that's higher level for the Extra Spell feat?