Thread BX5 Monitors volume knob issue (Probably valid for the whole BX series)

Hello how is it going?

I just bought a new pair of M-Audio BX5 D3 monitors. When I installed them I set the volume at 9 o'clock (maybe around 2 or 3 in a 1 to 10 scale), and push my interface to a level of volume that felt good. They sounded kind of dull and muddy but I thought it was related to my room acoustics. Then I set the "Acoustic" switch (basically a highpass filter) down to -4db and have some improvement on the muddyness but the sound wasnt there yet. I kept thinking it was an issue with my room so just started thinking on how to tame the bass response and maybe set some diffusors.

When making my research I started to listen to music and, not for any particular reason, I decided to set the volume knob higher (from 12o clock to the maximun level) and lower the interface signal. Accidentaly I found out that the monitors really shine and had a great sound on the zone above 3 o clock to the max level. I didnt have any noise issue or any other problem related.

Then I read some faqs from M-Audio oficcial page about the BX8 (not the same model but the next level monitor on the series) and they recommend to have the volume knob around 12 o clock to 3 o clock in order to protect the monitors and as the "best practice".

Finally I did some basic tests with a setup that was not ideal, but I wanted to check if my mind was not cheating on me when I put that knob at top. I just put a basic condenser on my listening position and send pink noise over each speaker separately. My listening level to be confortable was around 69dB to 70dB (measured with a cellphone). I found out that on that level there was a difference of almost 6db on the middle high frequencies (around 2khz to 4khz) and around 1dB to 2dB on the high frequencies (above 10khz) when I took the knob near the max position.

My question is, is it a bad practice to have my monitors near the max volume level, can it affect its lifetime?