I guess you heard this a few times already but they arent working as their description says and your explainations doesnt quite hold up either.
In their description they are said to increase your drop chance but from your explanation they just decrease the time needed for the pity timer(?). a pity timer that by all accounts are set to something really crazy and unachiveable.
I have played quite a bit since the start of the event, way more than you would expect to play for a drop and I got boosters. I could be the unlucky one but from ppl I talk with a lot of ppl seem to be that 1 in a million guy. To top things off we got tons of ppl like this:
http://forums.dirtybomb.nexon.net/discussion/comment/172987/
My main grievance is the bad explanations, the bad claifications (we still dont know how the work) and that a lot of ppl get without any boosters day1 G_G. Dont think I heard anyone getting a case except for the first day of the rotation or with 10 boosters so I question your claim that they work.
Next time just remove the drops and sell the cases in the store for money/cycles/credits and if you are feeling generous, reward them like you did with trinkets and/or from a special event quest.
(dont got a good play time for reference but Im at ~120 cases with 5 boosters)