ANR performance isnt all the same, your comparing two things at eother end of quality scale
Ive done 2 Headsets inc conversions, both excellent for 400 hrs so far
I have hardwired powersupply on one and portable box on other which doesnt get used much
Never had issues with non anr headsets but did have to fit ferrites as they can pick up signals near big radio installations
Somewhere theres an old magazine comparison on ANR performance and Headsets INc kits were up with the top end units