Also, if the frame is measured from the crank center to the top of the seat tube, the standover height would be lower if the intersection of the top tube and the seat tube is significantly below the top of the seat tube.

Case in point; both of these frames are sized as 24" from the crank center to the top of the seat tube, but the Super Sport has a significantly lower standover height (~1"):

'72 Paramount:



'73 Super Sport: