Regarding anybody that has used QA1 front uppers and on lowers on 1964 to 1966 valiant

So i got my custom rims. But im wondering if they did it right. When i set the 4" backspacing rim i had it was 2inches from the leaf spring. And now when i put the "so called" 4.5 backspacing rims. Its only 1 3/4 from the leaf spring ? I think the shop made a mistake ?

Also where is the backspacing measureed from. Check the pictures