The edge on the slot game is higher than on the dice, so the Kelly criterion allows higher bets.

The SatoshiSlot has a theoretical payout percentage of 96.5%. This however cannot be determined to the same precision as the dice, as in the slot the RTP/edge is calculated by a simulation, known as the "theoretical payout percentage" or RTP, "return to player".
The max bet on the slot game is not automated as on the dice, it has to be done manually. The slot game has many paylines, it doesn't really work well if the bet sizes on the slot game would be in increments of 14.235, 18.503, 26.322 instead of 10, 15, 25 ect.

There are similar wins with lower bets. Overall, Satoshidice paid out more than the expected value to investors since the start, meaning that the bets actually generated more to investors than the expected outcome.

If the bankroll decreases further or more investors have an opinion about it, we will lower the max bet.