Unfortunately, I think the active hours period cannot be set to more than twelve hours, which is less than the time required for some surgical interventions. I can almost imagine it: OK everyone, ten-minute break while Windows installs its updates, this guy who's been on life support for the last ten hours can wait a little longer.
That's why updates are not forced on business-grade installs, and forcing them would be a very, very stupid decision.
Forced updates make sense for home users, since Microsoft can't depend on someone requiring them to keep their networks secure. For other types of users, second-guessing update policies is always a bad idea.