Wolf, I'm not disagreeing with your experience, as I too, have had experience with the Nak amp, and 200 watt Adcom amps with this type of LED indicator. It will be very easy for these LED's to blink when using speakers with an 85-86db sensitivity in a larger room, playing music with a wide dynamic range moderately loud. I'm sure you realize the amp/speaker relationship is logarithmic, and not linear. A very slight increase in a dynamic peak will require quite a bit more amplifier power.
Here is an article about this amp using different speakers. Check out the next to last paragraph.
http://www.tonepublications.com/old-school/nakamichi-pa-7-amplifier/
Joe, download the manual for GFA-5500 here, and read the section "Instantaneous Distortion Alert LED's". This is basically what a manual for the PA-7 would say.
http://www.adcom.com/manual/cat_view/68-manual/44-stereo-amplifier.html