(just another student of these arts here so take with a grain of salt)
Honestly, these all look like good/useful tests. If it were me I would probably set my AeT at 125 (or maybe 130) and proceed from there and retest in 6-8 weeks.
I think you may just be falling in to a common error of what I think the coaches have labeled ‘false precision’ in previous forum conversations. You have done all the rights things – yay you! (warmup, controlled environment, consistent time of day, etc) But even after we control for all those things the reality is respiration and heart rate are still imperfect tools and a complex output of not only our workout but also other life/environment factors.
For example, in my own training I routinely notice easily a 10+ bpm variation for a variety of hard to control for factors (time of day, poor sleep, life stress, heat/humidity, excess fatigue from prior days, dehydration).
I have come to accept this imprecision and thus try to error a little on the conservative side, hence why I might target 125 vs 130 bpm in your case even thought both are probably fine. Also knowing my own nature I tend to push too hard so a conservative boundary gives a buffer.
As a cross check you could also gauge next day fatigue for a normal length AeT workout. I think the general rule of thumb is you should feel reasonably fresh the next day (like you could repeat the same workout) and if this is consistently not the case then you might benefit from dropping your AeT target (try 5 bpm). Note: this might not be a reasonable gauge the day after your ‘long hike/run’ of the week at AeT simply because this longer hike/run is designed to drive higher fatigue.
Curious to hear what others think and good luck,