I don't see why it being 'last minute' would make it worse than it being 'a month before already prepared since a year'

.
Seriously, don't we all push up that essay to the very last evening, and then sit all night, and get the highest grade regardless? Haha.
No, but honestly, that they make a lot of work during a few days doesn't mean it'll reduce the quality, because I think they spend an equal amount of hours working as if they'd do it earlier. Also, now they don't have time to procastrinate during the process, they have to stay focused on what they are doing in order to complete it.