You've never heard of that method but you know where the measurements are taken???
Well in your OP you stated that your
pants inseam was 29". While I don't recall ever hearing of the 109% method. I certainly don't think any useful measurement for cycling fit will be based on pant size. However many are based on the length of your leg.
So please chill, your OP is not without plenty of statements that can be taken more than one way. And there is no direct question ask IMO.
It's not my wish to offend you, but you keep calling me out. Ignore me if I'm not helpful.