you speak in logical thought, but in my experience the boss does not care about that. you are expected to do the job in the time allotted and any failure is your responsibility even (and especially) if they pulled you off of that to deal with “more important” priorities in the middle of your work. you will be dinged for failing to complete it by deadline.

this was eventually used to justify laying me off at my last job even though i usually pulled it off.