assuming your app is the same as mine...
if youre just cloning the profile and selecting BC instead of 4DOF, it changes the bullet selected to a different bullet in the same caliber family
why idk, but double check your actual bullet in the BC calculator...maybe a bug...maybe the app doesnt tie the 4DOF data side to the BC side and it just selects a default bullet
for example, my 4DOF 6mm 108 berger profile....if i clone it, and select BC calc instead...it changes the bullet to a 6mm 65gr Vmax bullet even though it clones all of the other rifle data