Let me answer you on Behalf of Hhampuz.
If you Look at the Requirement Section, It clearly says; You'll be awarded "up to" $100 based on the details, your standing here on bitcointalk and how extensively you've tried out either fast, note or both of the ways you can mix your coins at whirlwind. It says up to $100. So, It's not guaranteed that even the highest standing will help you get the highest reward. They also mentioned that if you add images or even recordings to a text-based review, You increase your chances of higher payment. I don't see any screenshots in your review post. Also, Your standing here on Bitcointalk is not too high. Just shared my thoughts.

Still, I believe any rank should be paid over $20 if they tried fast and Note both features since it will cost them a minimum of $10 as fees.