Phil:
Maybe I did not express myself properly. I'll try again.
From the user's perspective, there's a pad (On/Off) to flip the power to the burner, then a LED with two characters, and three pads: Hi/+, Med, Lo/-. You turn on the burner, and press either of the 3 pads and you are taken straight to PowerBoost (Pb), Med (5) or Lo. After that first press, Med continues to take you to 5 at all times, but the other two pads become + or - to raise or lower the power.
If you cycle thru the power, what you see is Lo, 1.2, 1.4, 1.6... until your reach 3.0, then 3.5, 4.0, 4.5 etc until you reach 7, then if you press + you see 8, 9 or Hi.
It's more or less like a rotary knob on a standard electric burner, except that you use +/- to go up and down and you see the numbers on the display.
Behind the scenes, it does what you suggested, which is, the controller offers more gradations on the lower power range than on the top. It seems to work relatively well, I rarely miss an intermediate step between 7 and Hi, and I always find a convenient setting to keep food just at the melting point of butter or chocolate, for example, without burning. It's easy to bring a pressure cooker to operating pressure/temp and then find a setting that keeps it there without cycling up/down.
What I did not know is why they did not make the power linear with the numbers instead of the strange curve they picked. If they are trying to behave more or less like the old 5 step burners for people following recipes, it kinda makes some sense. Also, I had no idea the power curve is what it is until I looked at the tech sheets.
For what's worth, I never actually measured the power in a burner with infinite heat knob. For all I know, they cycle linearly (7 is 70% of the time on) but the effective power might be 50% like Tom says Med-Hi should be, I dunno?
In any case, yes, I agree with you the affordances are suboptimal, a knob or a control more like what Jon showed here from the Café is better.