Say that you have a section drawn at 0+000 and one at ~0+003.3 and then the next at ~0+010 or something. Then maybe the solids extracted only equate to the area between the first to sections. You could try to increase the frequency to see if that is indeed the issue.
What you’re currently pulling is just a single solid between the corridor section intervals, which is not an even number, as shown in your AppliedSubassemblyShape.Station node output.
You’ll have to extract the solids before/after the location you’re looking at and trim those down to get the total length you’re after.