Why this obsession with QNH readback nowadays?
There are only three cases where it is needed to be read back or confirmed:
1) On or before first cleared altitude on departure,
2) On first cleared descent from a FL to an altitude, and
3) If the QNH changes.
Anything else becomes either ATC clutter or potential for confusion.
End of story, surely ... ?
you say 'if qnh changes'...but how do we know what qnh you have? I can only relate to aerodrome ops but on start up, you could have anything in there.
One day a few months ago, the QNH dropped 10mb in an hour. If you missed one (regular) atis, then you could have had a qnh setting leaving you over 300ft out from where you should have been.