So not only do you have to hope the RNG is on your side for the Tenks drop, you have to hope the one you want spawns first? I dunno boy.
Yeah, it's messed up.
I have an SA 10, an SA 5 and another 4 copies of Skinnytenks and only 8 Fattenks.
The drop rate itself isn't bad at all, but having to wait for RNG to give you what you need sucks.