I think every shoe/boot fits a little different. Mondo is just a goofy word for the size in CM and since cm are much smaller than IN I trust that number to be more accurate for sizing, also b/c I grew up in Can and learned metric 1st lol. I also think that some of those conversion charts aren't very standardized in regards to US sizes. I was looking the other day and based on the size of my foot in IN's the charts conversions ranged from 8 - 9.5! So who the heck knows man.