I am nothing close to an expert on this, but that is how it happened last time. The Iphone store update came on a Wednesday, and the Android store update the next day or something. Then on the Monday the timetable released.
I assume they use contractors for the various apps and don't do it themselves, perhaps they have to wait until the app is available on all platforms before the news can be shared? So i guess they have to allign these things with certain parties.
I would prefer they just release the timetable on the website with a statement like 'in the coming dates the app will be updated'
but since we saw the news article with a title 'apps have been updated' we know for sure that they are not taking that route