My B mod and C mod Acoustats

I am still struggling to define the difference between my two sets of Acoustat 2+2's.

It's certainly not just a matter of B mod vs C mod.  It's also that the level control was adjusted downward on my first 2+2's.  I adjusted it that way thinking it was flat, but it was actually 2-3dB down perhaps.  And I also liked it that way, in fact EQ'ing down a bit more.  Though it might be better flattening out above 12kHz rather than continuing on a downward slope.

But I haven't adjusted the newer-to-me B mod speakers to that same level, because it's a bit harder to do, you have to open the interface case and fool with a strap (which requires deoxit cleaning).  I'm now very certain I like the old knob level control better, but there should be terminals you could measure for exact settings.  (Actually, in the older interface style, like my first speakers, with the original A mod in them, you could measure the DC resistance across the input terminals to set the HF level repeatably.  But since mine have C mod, I can't do that, and have to break the case apart--difficult in the older interface style--to make measurements, which I'd been planning to do since forever.)

Also, I wasn't even sure whether I liked the greater HF output or not.  It looks like it might even be objectively an improvement.  And sometimes I've thought it was.  But I'm leaning the other way right now.

But there could be still other factors.

What's really mind boggling is that the newer-to-me speakers (B mod, higher HF level) sound a lot louder.  So I adjusted the level downward, finding the matching point to be about 2.5dB.  After making that change, a lot of the added "punch" of the newer-to-me speakers went away.  But they seemed more similar if still different.

Anyway, objective level measurements don't back this up at all.  In fact the C-weighted pink noise of the newer-to-me speakers doesn't measure louder...it measures 2-3dB softer!  Changing the weighting to pink noise brought the two speakers much closer, but with the newer-to-me speakers still about 0.5dB softer (about the margin of error).

Note that this is still with the newer-to-me speakers in front of the others, which seems to make surprisingly little difference.

The 'louder sound' of the newer to me speakers was especially apparent to me with pink noise at a high level.  At levels I used to think OK the newer speakers sound overwhelming, whereas the older ones sound slighly distant and unfrightening.  (And this is with the C weighted noise of the more distant sounding speakers actually being 2-3dB louder!)

I'm still finding the 'harder' sound of the newer speakers to be sometimes bothersome.

So I don't know what the issue is.  Is it that the B mod has more distortion, making it 'sound louder' ?  Or is it that some of the old-to-me speaker panels have weakened?  Or is it just the HF level difference?

Should I swap my old modified C mod interfaces in, and with or without adjusting HF level to -2dB?

Should I just reset the levels in the newer interfaces to -2dB (which isolates the level change)?