For the uninitiated or new to Lexus, when the car is due for service an annoying service due message pops up every time you start the car. Since the 2016 model year (I think) you can turn off (reset) this message via the dash menu system.

 

Just to be clear, what you did does not "turn off" the service due message, it only resets it for another 5000 miles before it comes back.
As far as I know, there is no way to completely turn off the notices.

 

Correct, it is a reset until the next 5000mi.