https://megous.com/dl/tmp/a4111a84934c8c8f.png
https://megous.com/dl/tmp/1eccbf102295a676.png
It's not like you go directly to 20, you go one step at a time.
> Sources can support more and it's not against the spec, as long as you detect the 5A cable.
They can but how many do? If you want to play nice you shouldn't require that for your device.