Comment by Quekid5

Ideally, yes.

In practice there are often complications, however.

Usually, it's just office politics: Those cases can be quite difficult -- you really need buy-in and TRUST from management (and have to do the right political plays, etc.) to be able to cut through the bullshit and "allow" feature slips. Books have been written about this scenario.

Rarely, deadlines are imposed by Real Politics, aka: law... which can make for Interesting Times. This can range from "quite difficult" to "too easy!", so I have no advice here.