Wut? 15-20%? Let's say I wager $1000, I could get $150 back? Sounds too good to be true 
But that's possible if because of lossback, since you do all-in most of the time.
IDK the system work ~LOL, the calculation may be sound different from what's u did.But that's possible if because of lossback, since you do all-in most of the time.
But here some screenshot from the old "Roowards" I found on twitter, they even got 24% for the next level. 15-20% sometimes could be active when roobet make some event for the "Roowards System"
