A simple hyper-conservative approach is pointless when you have extensive testing backing the data. You're so far outside your lane and you're completely unaware. Look at the graph again, think about where you fall. Did you read the SAE J2807 standard? Come back once you have.
Edit: I'll even give you the link! Can't wait for you to try to explain why a peer-reviewed industry-accepted technical standard is not good enough.




This document establishes minimum performance criteria at GCWR and calculation methodology to determine tow-vehicle TWR for passenger cars, multipurpose passenger vehicles and trucks. This includes all vehicles up to 14000 lb GVWR.
www.sae.org