Both the MAF and the nose breathing/conversational pace methods are attempts are approximations of your aerobic capacity. The MAF formula tends to give a very conservative estimation of AeT and for those without much history of low intensity long duration training (by HISTORY I mean years of focused training program) it is probably the best number to use (baring Lab Test results https://uphillathlete.com/getting-tested-part-1/). For those with extensive aerobic training background the nose breathing/conversational pace (ventilatory test) can give a decent correlation with lab testing and blood lactate levels.
People with a history of most of their aerobic training in Zone 3 be that in CrossFit style workouts or just racing up the trail to the base of the climb as fast as their less will carry them, can not get reliable intensity info from using the ventilation rate/depth test. For them the MAF approach will give more reliable info.
Since you live in he mountains, find a long hill and hike/run up it for an hour at your MAF HR and time yourself. Go back a few weeks later when in a similar fatigue state and do this little time trial again. Over the course of weeks/months you will see a drop in the time for the same HR. Voila: Improved Aerobic Capacity :-). When you begin to see a plateau in the time drop then you have you can bump your AeT HR 5 beats in training and start the building process again.
I hope this makes sense,