it may be what you are used to, and your best bet would just be to stop switching back and forth and abandon EQ for a while. You could just use the Black Label's preset bass boost if that's how you prefer music.
as I mentioned, I'm obviously not versed in whatever the terms commonly used are, but what I have a problem with isn't so much a matter of taste rather than a delivery of something different than what it could/should be. I would attribute what I mean is to something like the textured surface of something, where flat would be less and less texture and vice versa. To illustrate as you pass over the surface the tones would be rising and falling kinda like how vinyl records work.The magnitude of difference being, particularly in the reference song, the imperceptibility of the AFC as I have it at default is such that this proverbial surface responsible for bass might be quite the flat and polished surface, the other surfaces of the song are quite textured for the afc, but the bass is not. The far cheaper DT1350's have the opposite problem, but the difference isn't as pronounced as that with the AFC.
The main problem I'm having with all this is going back to the reference song and the proverbial surfaces, where the piece has a fairly textured bass surface, the AFC renders it as being smooth and without detail.
From what little I've been able to learn about planar magnetic vs dynamic, lack of detail shouldn't exactly be a problem for planar magnetic, but again I don't know much.
That's how I ended up here asking if it's normal to be missing bass detail. (Before the amp, the bass just didn't exist, I had hoped all my problems would go away with the addition of an AMP, but now I have a bass presence, but again, it's not detailed. it's as I've been calling it "flat".
I've been playing with various positions too, trying to just see if there was any given headphone position that was better than another. I did find a spot more optimal than what I was using, as far as headphone seal goes, it's fairly well sealed per your suggestion of running a finger around it.
I threw the foam pads in, the bit of extra material to pass through seems like it's just so I can put more power through them comfortably with something along the science of longer / slower waves traveling farther / penetrating better so you get a better bass response? Just a shot in the dark based on what I noticed, but I'm all ears for why the pads are actually better.
I'm NOT trying to come across as hyper critical of the product, I just have a goal and am curious of how to reach the goal. I'm beyond happy with how well everything sounds compared to everything else I've used, sans bass, and I would just be peachy if I could figure out how to make it work. (I recall reading somewhere you started by modding headphones yourself... so maybe you could appreciate what I'm after here. I figure step one is talk to the guy who hand crafts the things and still manages to be down to earth to talk with his customers, see if the guy could offer some insight, point out complexity of what I'm asking or even simplicity if it's a matter simply solved.)