Thread:Marekos1996/@comment-3466679-20141027154233/@comment-1856476-20141027162951

There are actually two kinds of production codes: one for each 10-minute segments and one for 20-minute episodes (often connecting two separate segments). For example Doof Dynasty is 311 and Tri-Stone Area is 318, but they're 308 as a whole. Save Summer is 427/428 as one-hour episode, but is divided into four 10-minute segments numbered 449-452.

Look at the numbers ;)