After some light testing at home, I have so far reched this conclusion as to why it is harder to steal in the door compared to the MBBS version. The door apparently requires you to divide your experience by 30 to find the amount of holds you can safely steal, rather than 20 like the MBBS version.

This leads me to believe that while it may take longer to get the required experience, the amount of money you will make will be greater since the number of busts overall will be lower.