Except I had a typo in my spreadsheet…This is a good data point. It's important to know that just because a torsion spring is only 14% larger diameter doesn't mean that it's 14% stiffer, it goes up exponentially.
Some quick maths (28.87^4/25.5^4) tells us that the non AHC bars are 64.3% stiffer.
I had the AHC bar entered as 25.2, when it is really 25.5, so the corrected numbers would be +3.37mm or +13.2%