But the result was (very likely) correct. As a mathematician, you should have no problem figuring that one out, looking at the finish photo and doing some basic calculations.
But the problem is indeed that riders and fans have no idea where the line is. This comes from the technical limitations of the technology that is used. Unlike a regular picture, a finish photo is more like a scan than a photo. Remember those old handscanners from back in 1991? (A normal scanner works the same, but this is easier to visualise) It scanned the image as you pulled the scanner over it. A finish photo works in the same way, except here the scanner is fixed and it scans as people cross it. But in order to get a clear image, the background has to be white, so the idiots set it up on one of the wide white stripes before or after (they even get to chose) the black finish line. The solution is simple, make the actual finish line white, with two somewhat thicker black borders and thén two wide white stripes. That way the finish photo can be taken on the actual line. Possibly it will need to be a little bit thicker than the black one they use now, but considering the black one they use now doesn't count anyway...