It really does not matter what the house edge is. As long as it is positive then your bankroll will be bleed dry eventually. It can be .01% or 35%, it really doesn't matter. After enough rolls at the certain bet then you will lose. Now that it is public, I am sure that more people are going to be quick to try to exploit it, so don't be surprised when the number of rolls that people are doing is going substantially up all of a sudden but your site's earnings seems to be going down.
This unfortunately is true as well, if more number of users going for those higher payouts chasing +EV, the sooner your bankroll will dry. I wouldn't matter much if someone was doing it individually, but now collectively your bankroll is at risk. Its not a very time consuming fix, I am sure you can do it asap.
simply changing the multiplier to be dependent on the win chance should be a nice and easy fix for this issue, currently the win chance is set by the multiplier which is set by the player, causing the rounding issue.
lol, i like how some people are taking advantage and using hufflepuff as their nick
now this i gotta see