I dont think they've tweaked something, it is just a pure luck on what numbers you roll every hour. I have rolled 999x 2 times if I remember it correctly but it was long time ago when bitcoin is not that expensive like nowadays. I registered on this site since 2014, so it is my 3rd year being freebitco.in user and I only get high number few times. A month is nothing mate, just keep on claiming it as many as you can. One day you'll roll high number. It is a matter of time and luck