User blog comment:KatyKat20/Which of the 3 episodes left of Season 4 are you most excited about?/@comment-1874176-20101226215852/@comment-1874176-20101227134535

It has to exist due to logic.

Episodes of season 4:

iGot a Hot Room (Code 301)

iDo (Code 302)

iSell Penny Tees (Code 303)

iGet Pranky (Code 304)

iSam´s mom (Code 305)

iPity the Nevel (Code 306)

iHire an Idiot (Code 307)

iStart a Fan War (Code 308/309)

 Code 310: MISSING!!!

iParty with Victorious (Code 311/312/313)

And I don´t really think they messed up their production codes and "forgot" number 310, I think they held back on information about this one on purpose.