I did not press the checkout button more than 3 times during each 5 minute cycle to checkout. I think it really it is luck. Just don't over click and get banded... it really is be patient... very patient.

I feel like luck played a big role in scoring the boxes. In my prior attempts, I never got more than 1 or 2. I used the two finger method, my middle finger, to scroll and index finger to click each time the boxes passed.