28 inches was the 'norm' for the industry- pretty much all bows were marked for their weight at 28 inches.
When the average guy or gal would buy a bow it was done based on the draw weight at 28 inches- even if it was to be drawn and shot at less or more than that..
Factory bows virtually all done that way. The older bows would have 50XXX at 28 inches; which was one pound per X - so it was a 53 pound bow; and xxx50 was a 47 pound bow.
Everything was relative to 28 inches.
Bowyers now would not put 50xxx@28 they would write 53 @28.
If you special order a bow; they will match it to your needs; by using all their magic.
I buy 60 pound @ 28 inches and draw back to 31; and shoot the same weight as my bow that I had made that says 74#@31.
I have never had a problem shooting past the marked weight with any bow.
Then again I am a new comer; only been doing this for 50 years or so....