I think he was suggesting that if he hit 191 on a bike ride and didn't feel like he needed to collapse, he was probably not at his actual MHR. He's linking to the Joe Friel stuff because it deals with LTHR. Friel doesn't like MHR systems because actually measuring it can be difficult to do and formulas are just best guesses.

In terms of LTHR, it's possible his is as high as maybe 180. Mine is about 175. The problem with the ride posted is that he's pushing at or near that threshold (which is usually pretty consistent for an individual regardless of fitness or age) for a lot of it and having so-so results in the avg speed department on a really flat ride. Working at training in specific zones will help to build fitness and produce even better results at lower heart rates.