What this test showed is that you are a very well fat adapted athlete. The MAF numbers you mention suggest you are 62 years old. It you are sure the max HR you saw was accurate (collected with a chest strap monitor) then you have a very high HR for someone your age. In my experience the MAF method will typically err on the conservative side in finding your AeT HR. I understand his idea and over a whole population the 180-age formula may give a decent idea of average AeT HR. But there is a great deal of interpersonal variability in HR response to exercise. At 65 my max HR is now about 168. That’s why we prefer to do some sort of individual test like the one you did or on described here.
These tests show your personal response and do not rely on formulas. Normally I would call the top of Z2 (the AeT) the HR you reached at cross over or RER=.85. In your case that is 165 and my gut tells me that is too high to sustain for hours. So, I recommend you do the HR Drift test described in the link above. This is a performance based test not a lab snap shot. Another good verification that you are training below AeT is that you can get up tomorrow and do the same workout you did today. You will recover in 24 hours.