If the "same size box" was so important to them, why didn't they take the largest car, scale it down correctly, make a box to fit, and then put all the other models in the same size box? Too logical???
And besides that... a '59 Impala was 211" long, a '59 Cadillac Fleetwood 60 was 225" long, a difference of 14"... or in 1/25 scale, less than half an inch. They couldn't fit a 1/25 scale Impala and a 1/25 scale Cadillac in the same size box???!!!