Before that date, the 380 is in the timetables. From that date, it's not. That is consistent with a change being made at the season break, as so often happens. In that sense, 27 October is the first day that the 380 is out of the timetable.

But nobody can tell you that it "will" be one aircraft or the other. Everything is liable to change, at longer or shorter notice. You cannot be guaranteed to fly on a 380, whenever you book and for whichever flight you book.

What you get from the published plan is a reasonable assurance that you are likely to get what is currently planned. But "likely" means only that; it is not the same as "guaranteed".

For an example of a large-scale short-notice change, see this thread: https://www.flyertalk.com/forum/brit...t-changes.html - the daily 380 and the daily 77W were swapped less than three months before the season started.