As others have pointed the scale varies based on which dimension you are using to calculate the scale. This because the proportions are not correct in the model. As Swampfox calculated based on the width the scale rounds up to 120:1 that works out to be .1 inch = 1 foot. so the Depth would be 10.1 inches and the height would be 4.5 inches and to be exact the width would be 22.8 inches
What is important does the model look proportionally correct as in pleasing to the eye and they are indeed pleasing to the eye.
I think I should have just said that I like the models and they look great.
There is a very fine line between paper modeling and mental illness.