Found it: It was by doing prestige when a bonus popup appears. Seems like it gets triggered and boosts the next run by 20 or something.
At first I tried spacing the max buy all, and going to the nelson scene before prestiging. But then I noticed the bonus on one prestige and then got confirmation. I then prestiged with no bonus on sight, back to normal. Another prestige with the bonus on sight and the boost happened again.
On another note, glad to hear the max issue was fixed!
After posting my comment, I came up with a little suggestion for the clothes and accessories menu: to change it to a drop down list (or a list box or similar). The issue happens after unlocking a lot of girls, since their clothes and accessories get added, making navigation with the left/right buttons a hassle.