[itishappy]

That's irrelevant. The speedometer reading is an absolute reference. The percentages being discussed are simply comparisons, and they're only being discussed to say "they behave like you'd expect."

To directly answer your original question: a reading of 21 is 5% better than a reading of 20 because 21 is 5% greater than 20, and this means that a 21 speed browser should do things 5% faster than a 20 speed browser.

TL;DR: They behave like you'd expect.

[lapcat]

> The speedometer reading is an absolute reference.

To what?

I talked about driving a car. Miles and hours are an absolute reference. We still have no absolute reference for Speedometer.

[itishappy]

To... itself? Go measure something. You now have a reference!

If you scratch out the labels of your car speedometer and forget which is which, it still measures speed. 80 is still 33% faster than 60, regardless of the units.

[lapcat]

This reply is ridiculous. I'm done.

[itishappy]

Suit yourself!

I suspect your questions would be answered better by playing around with the tool in question for a few minutes anyway, as you seem to be asking about capabilities the tool does not purport to have.