31.
Fairy Tail is weekly, and thus they want to get it out as quickly as possible. However, Soul Eater is Monthly. I'm assuming that they want to get out the weakly releases first, and then work on the monthly releases. Really, though, I'm not a translator. I don't know how hard it is to translate. And it's not just the translating, but the scanning of the chapter, and the cleaning up of it as well so it looks nice.
This chapter almost made me tear though, because Liz and Patty.. omg. And BS has grown so much since the beginning of the manga, it's just... wow.