Magnepan LRS+ resistors on the tweeters… which?

Currently, I have the feeling that I am in a middle of something with the LRS+… on one side there is the speaker positioning and on the other the amplification.
In some degree, the evaluation of one is connected with the other.

The Rogue RP-1 / NAD C275 BEE pre-power combo is performing very well and led to a new position of the speakers that finally I am getting a good depth and soundstage… but the treble continues a bit hard and compressed on some recordings.
With gentle acoustic music I am in heaven. 
With busy recordings with brass instruments (for example) it is not pleasant at all.

Also the LRS+ are really “power sponges” on some recordings, with the volume knob seeing untraveled territory… uff

Note: the speakers are on aftermarket stands, more or less 60cm from the side walls, 130cm from the back, toe-in pointing behind my head and tweeters on the outside. Treble resistor Mundorf M-Resist Classic10w 1,5 ohm.
Speaker and interconnect cables are Straightwire Encore.

For anyone wishing to try a bunch of different value resistors check out JF components they have many audio quality of under $2.00 each, I just placed an order myself. They also carry speakers and other audio components. 

@audiofilo123 

It appears this is part of the design.

https://www.theabsolutesound.com/articles/magnepan-lrs/

Finally I have found the perfect partner for the LRS+: the Copland CSA70 integrated amplifier.
Spec wise it kind of defies logic, comparing to what most people (and myself) thought that was needed to feed the little Maggies, but it is a revelation!
This amp totally transformed the LRS+ and solved all treble issues. True, I still have the 10w 1,5 ohm resistor in place (too lazy to remove it?) but the sound is beautifully balanced, free from any sibilance or aggressiveness.

Absolutely every aspect of the sound gave a gigantic step forward in quality, especially the soundstage, the sense of transparency and bass delivery. No subwoofer needed in my 18 sq meter room. The LRS+ are indeed a miracle!

This is the entry level from the danish brand and can deliver 140w / 4 ohm, but most importantly it is designed to handle loads up to 1 ohm! Brilliant stuff.

I only wonder what the CSA150 could bring to the table… but I happy with the CSA70 and my bank account too, so case closed :)

Putting a resistor on Maggies to solve a HF problem would be a last resort for me. Placement, toe in or toe out, different amp, tone controls, PEQ, etc., would all be tried first.

Why is it a last resort? If a manufacturer put it on the crossover instead or a guy like me sold you a modded (’non bright’) magnepan and you just didn’t know about it, everything’s ok then?

Wondering what the logic is around here.....Is the key here that you didn't know about it (so some belief system didn't intervene)?