Well, I think the deadlines for milestones are more or less fixed, so they do not account for possible surprises.
v7 has introduced a lot of changes and there were some serious bugs in 7.0.0, 7.0.1 fixed some but certainly 7.0.2 ended up with a very long list of them and the deadline was just not realistic, but again I think the calendar is fixed for releases. I would take the deadlines with a pinch of salt until v7 reaches a more "stable" status.