I agree it would be great to know the actual date. But I like the added strategy of the uncertainty. It makes the decision of when to start an upgrade more interesting, as you can't be completely certain of when the upgrade will be finished.
I think the thing to keep in mind is that nobody has ever complained that their seats were ready too soon, so upgrading may be best served a few weeks before you actually need the seats, just in case you get the construction crew that goes on spring break with the job half done.