Not all boots are the same just like not all feet are the same. Going to a bootfitter allows someone who knows how to get you boots that fit your feet and are the correct flex for what you plan on doing ie. park, racing, tourning, hucking, ect. ect. Make sure you pick a boot fitter with a lot of experience not some guy working at a ski shop who says he'll "get you fitted for a pair of boots"
Just because you have a preference on a certian brand or style doesn't mean you can find one in your size because some boots are made to fit feet built different than yours.