Is Bloodweb perk roulette actually working right?

I'm starting to suspect that the bloodweb lotto doesn't actually value the perks equally. Here are some reasons.

1. I've leveled about 150-170 levels of killers since I bought Enduring teachable. The perk has not appeared even once.

2. I'm now halfway to 3rd prestige round on Hag. I've never had Iron Grasp, Deerstalker, Brutal Strength or Enduring appear. Instead the same perks always come up.

Is there something wrong with the web or is it just my luck? I'm really tired of getting the same perks over and over in almost the same order.