Maybe they're compensating for something

from here

Eleven zero days is an awful lot of zero days.

And each one is worth an awful lot of money. 

Stuxnet only used 4-5 to compromise nuclear enrichment facilities and set back Iran's nuclear weapons program by years. This group better hope whatever they're doing with 11 is worth more than what they could have gotten by selling them, or they are going to be so pissed.