What can i say, that x312 wasn't bad at all with a $2 bet... But for a Super Bounus i was expecting the x50,000 (Max win on that slot). Walking away with $100k would be fun. 
We all expect that to happen but God is cruel when it comes to showering the blessings. 
It's not the change of machine/game, I feel it's due to the change of bet amount that increased your gambling session for sure atleast 5x with $2 bets rather than going with $10 bet per roll. A tip you can consider though, bonus feature increases the changes of winning a lot higher and I always feel like atleast we can able to recover the bet amount 50% of the time even if the roll is pretty bad,
BTW, why does it say free demo on the top?