It's most likely a trained behavior thing. If most of your experience of music is from your HD560 unaltered, you are obviously going to think things should sound that way. Which is really fine, as long as you like it. BUT what all those targets are trying to simulate is how a perfect planar speakers would sound in their version of human head with ear canals would sound like if it were placed in the middle of acoustically neutral(?) room. Also, don't take those AutoEq as some sort of end all be all type thing. For one there are many different targets, and at least two very well stocked repository of AutoEqs. One thing that bothers me is some of them AutoEqs have frequency orders all jumbled up. First thing I would do with those is download the parametric Eq file and read it in to EqAPO. Then open them up in a separate tab and reorder them in either ascending or descending order. Then start looking at what each one is trying to fix. You may find some not so useful or some that make no sense at all. Once I find a target AutoEq I like, what I do is do aforementioned steps and then leave what I think is good. At this point you are 80 percent done coz you found the target feels natural to you from upper Bass to Lower Treble. At this point, I start listening to a set of tracks I listen to a lot, so I know what to listen for. Youtube mix track works well, as long as you have a plugin, that sets all the loudness to equal level in your browsers. Then I decide how much bass low-shelf I need to apply at around 120Hz. Do I need more or less??? Then I listen to high treble range and do the same but with high-shelf at around 8-10kHz, sometimes even up to 12kHz. Depending on the headgear. Assuming you have pre-amped all your eqs down to 0dB max and you are on PC, you actually have about 3dB headroom. And the very last thing I do is actually apply high-pass at 10~30ish Hz to prevent my VU meter from going nuts and make it easier to drive my headgear. Also, depending on headgear spec, I also apply low-pass at around 22~24kHz coz we don't have animal hearings. :D

You know way back in the day, there was a phrase high-end Euro automakers used to use. Don't worry about the details, it all depends on how much money you are willing to give us. You won't regret it. This was before tuning got popular in the 90's on.

This is why back in the 90's people tried to make a smallest well tuned loudspeakers to hang over ear. ;P Bypass all the problems with having to deal with human imperfections.

All day pretty much.

Short answer, YES. If you are happy with your eq. I suppose it's your decision. All I am saying about those AutoEq things is that they use a well established target and makes life easier when dialing in your own Eq. I thought I could do it by ear too at first but really I go no where in my experience.

Ok in that case find one of those frequency sweep sounds on youtube or other places and listen with AutoEq applied. If you notice an area that bothers you you can adjust AutoEq by adding parametric Eqs.

My advice is to apply one of them AutoEq first and decide on the bass low-shelf. Makes things much easier. I mean even expensive headsets/earbud/IEMs sometimes do some crazy roller coaster ride through the frequencies. @.@...

Setting base low-shelf beyond 150 Hz will muddy up the sound. Recommendation is around 120-130 Hz. Also with such high shelf assuming you are doing earphone/headphone corrections, you are most likely clipping. You may wanna figure out the max on your system and tone it down a bit. Also, adding some convolution reverbs of locations you imagine your music is being played may add to much enjoyment. By headphone eq'ing I mean: https://github.com/iwalton3/AutoEq/tree/master/results_ief_with_bass.