Wait, really? I had always considered that was simply a bonus that was added on top of the base 200-20-2-.2-0.02-0.002 pay structure and that it decreased each free roll you made, until it hit the lowest base amount (0.002). The bonus wording on the text does also help believe that...
If you get the low wagering reduction the is a I next to the value on the payout table and if you click it you'll be told to wager to get back to full base reward. The bonus box is about increasing beyond the base reward up to 19x added.
I do remember that sometimes during 2016/17 my base rewards were cut in half sometimes; I could have a base roll of 600 satoshis one hour, 300 for the next 2 and back to 600 then. The price wasn't fluctuating that much, but I never got any actual reply to why that was happening.
When we still had adverts on the site they paid according to your location so users in high paying areas of the world got more. The IP addresses you were using must have been listed as different counties (databases aren't 100% accurate).