Well, searching on the Net I catched a "Ferb Latin" song audio so odd, 'cause it don't have SFX - sounds and effects - or the complete duration, but, rarely, this audio have much more voices in chorus and more instruments sounding, O_O
http://www.youtube.com/watch?v=vkTPD0Z7TA4 (it's just a look, I can't catch the complete song at the moment, :S!)
Could it be the OST version's audio? So early?
Oh, and Merry X-Mas! :D!!!
P.S. - I can't tell you how I got the audio (webs, links or something like that).