I read somewhere that the success rate of winning spins on lvl5AI had been deliberately increased from roughly 10% to roughly 15%. I don't know what to believe, but I know this: I've been Lvl5 farming for three straight hours now, winning 95% of my games, and I haven't won a single card all morning.
I'm very willing to believe that it's just a string of bad luck, but I thought I'd ask just in case something had changed on me.