One of the better Treehouses in a while. The Zombie Apocalypse in particular is one of the funnier bits the show's done in a long time. For this year:
Act I: Bart and Lisa agree to "solve" each other's teacher problem. CRISS-CROSS! Act II: Krusty's mad cow burger brings about the Zombie Apocalypse. Act III: Homer impales himself on Moe's brewer, giving blood-soaked beer an aphrodisiac effect on Marge.
The "CRISS-CROSS" stuff was pretty good, especially once Willie got in on it. The idea that the last act was done in a theater setting was a neat one in theory, but didn't quite lead to as much funny as I thought it would. Overall, a decent romp, as is normally the case with Treehouse.
I mostly agree with your point, but your numbers are mostly wrong. The latest monthly sold approximately 31,596 copies (http://www.comicsbeat.com/2012/03/01/indie-month-to-month-sales-january-2012%C2%A0/)