Ok. Sorry for the minimalist approach
.
For example: (where ATIS is saying) "Los Angeles Intl info Charlie....blah blah...maintain 5000...on receipt of your ATC clearance, read back only your callsign and initial assigned altitude."
The readback would be "Los Angeles Clearance delivery Barnburner 55 assigned 5000 " ..(then over to Ground for push and start).
My contention is that, with receipt of a datalinked Pre Departure Clearance (PDC) which has the same altitude constriction, my readback would be exactly the same , notwithstanding the passage in my company's Route Guide - part of the Exposition, issued under the AOC but, I think, of lesser standing than instructions issued by ATC at the time.
The other view is receipt of the PDC closes the data integrity loop and no readback is required.