I did not create that calculator. Don't yell at me about it.You can discuss what you think is wrong with it here:
Feel free to use this calculator. Add sensitivity to the speaker and then tell which effect you have chosen and why. Weigh in that you want some headroom. http://www.mh-audio.nl/Calculators/REAP.html You can select music from this list. Or something else, but in that case tell us how you...
audiosciencereview.com
Take such a calculator for what it is. Power to speakers. Bass drivers (especially sub bass drivers) require much more power than tweeters for example.
If you also want to EQ, more headroom may be required.
Another calculator:
View attachment 258378
www.crownaudio.com
Edit:
Incidentally, you want to listen at 85 dB, all else equal in my example then 200 watts are needed.At 95 dB listening volume, 2000 watts are then needed.
Try the calculators and you'll see. Nothing strange about this.