I also played this game recently and triggered the bonus round 3x with the double chance enabled and triggered it 1x in normal spins(sadly I failed to screenshot the result because it less than average).  I also don't get a good multiplier during the bonus round and even one of the four bonus rounds got zero tumbles.  In my recent experience, I got the bonus round much easier since it only took me less than 300 spins to trigger these 3 bonuses with double chance enable and another 200+ spins to trigger the bonus in normal mode but the reward somehow sucks unlike my earlier try on this game although it is harder to trigger the bonus but the winnings on the bonus is satisfactory