Time compression microwave

Food that has microwave cooking instructions on the label usually list times for a 650W microwave and sometimes times for a higher power microwave, for example 850W. Maybe I'm just unlucky but I never seem to find a microwave that matches the instructions.

My proposed microwave is more powerful than 650W but accepts times for a 650W microwave. It simply ticks through the seconds faster than real time. You enter four minutes, and it counts through them, stopping after maybe 3'30 of real time.

I realise that cooking times are not exactly inversely proportional to power (nor exact at all), but I think this would be better than my current process of thinking "Hmm, this is 900W, I'll knock off 15 seconds from the 850W time". My main goal is to simplify the instructions on packaging. I think manufacturers would go for this as well, as it gives the user a better indication of what they've spent their extra money on ("Wow, that four minutes flew by on my new 1000W microwave!")