My 8 speed auto drops down gears when you let off the throttle to slow the car, just like you would in a manual, it doesn’t coast in a kind of neutral at all.
As far as driving faster in an auto I don’t see what the gearbox has to do with the amount of throttle a person applies, how can it? If I want to go faster I press it more, slower I press it less, good luck trying to get out of a speeding ticket with the excuse “it was the auto gearbox’s fault, honest”