Not Ryan, but I think I can answer it.

The max profit is a number calculated by the height of the bankroll. Bustabit calculates the max profit by the kelly criterion. That basically means you can win (i believe it is this number now) 3% of the current bankroll of the site.

It does not affect the multiplier at all, except for the following: If everyone combined bet 2 btc on a max profit of 10 btc, the game cashes everyone out that is not yet cashed out when the profit of everyone combined reaches 10 btc. To make it real simple, let's say you are the only player playing currently. You bet 1 btc with a max profit of 10 btc. If you keep it running, the game will cash you out at 10x multiplier. Even though the multiplier could have gone higher.