I am constantly surprised at the use of wrong data in Archie-M. I recently had dealings with a viaduct with semi-circular spans. The rise of each span was recorded as different by up to 250mm. A careful check (with a total station) revealed that the error was in picking the springing level and all the crowns were at the same height. This made a substantial difference to the multi span capacity.
Time to say again. Stand back and look first. If the dimensions disagee wtih what you think you saw check the dimensions before you change your view.
If the spans measure differently, don't start analysisng but look for reasons for the spans to have changed.