I agree with you, I would just add that in software development it might be hard to guess how much time something takes. Also it is not that uncommon in some cultures to avoid say no (If you ask in Nepal whether the path leads to A, the answer is mostly yes, despite the fact where it actualy leads.
). Programmers promise to do something in certain amount of time, even thought they know it is hardly possible.
So, I would newer base my expectation on deadlines. It comes when it comes despite any deadline.