The Big Hauler products seem to be described as 1:22.5 scale, where the Spectrum line is billed as 1:20.3.  Is there a real reason for this?  Both products appear to be meant to depict 3 foot narrow gauge railroad lines, which when modeled in 45 mm track scale to 1:20.3.  The 1:22.5 scale with 45 mm track is a gauge of just under 40 inches. 

Is there a reason for this other than to create a distinction between product lines?