I've gotten $50 up to $500 a few times in the last couple weeks, but only after losing 4 or 5 $50 deposits first. Yesterday I lost $100 on 0.40 bets wayyy to fast. Also while I was playing yesterday, I saw two random jackpots get hit. This got me thinking that maybe the random jackpots are such a large % of the EV of RTG slots that unless you hit one the wins are pretty bad most of the time. As seen in the winner screenshots thread a couple days ago, I've been hitting tons of line wins, but no bonuses or free spins.
Also, playing tens of thousands of spins on many different RTG casinos I have noticed differences in some of the games. Maybe I'm just crazy, but I think that if they do change the payout percentages of the slots they do it by adding or removing scatter symbols from the reels. I swear I remember playing at a casino with only one scatter symbol on the first reel of derby dollars and I lost very fast. On the other hand, when I hit five scatters on derby dollars three times in a row, I think it had three scatter symbols on the first reel, because it was hitting on the first reel every two out of three spins or so before that I got the huge win ($732 on $1).