Same here.
Our solution for the last 8 years has always been to set the ship-by date to match the production schedule. (Don’t read anything technical into my use of the word “schedule.” I just mean “when certain people think we will build that thing.”) Whereas the date we show the customer is (IIRC) a UD date field.
But I agree; you are describing a better way – ship-by is meant to be an obligation to the customer, but we should be free to schedule the job independently as we see fit.
I never saw the point in making an Idea for this, but it gets at my concept of a “slotted” schedule. (Not just scheduling but also deliberately leaving gaps that can be filled in.) It’s what we do in practice, but I see no Kinetic equivalent of this.