you would pay for the 70lb bag on the 1 leg?, then hope for the next 4 ug and pay for any that you don't get?....
do you need the extra 20 lb at each stop?....do the bags get lighter as you go from place to place?....maybe ship some stuff to a later stop...i don't know the cost of a 70# checked bag, but you are looking at from 0 to 5 fees....good luck...