Bookworm,
You are right, of course, and I am persuaded
Why do I have the distinct impression that you have battered me in discussions elsewhere previously??!!
During the three months it's taken to get to this stage I have learned that it's far better to ask for 200% and be happy with 95% than to only ask for 75% at the outset

(I suspect you know what I mean)
What went on our website (
www.telecall.uk.com/ais) was a realistically obtainable goal - as you say, filtered to requirements of the various PIB users.
We won't be asking ICAO to change anything
Cheers
Russell