The short answer
They separate three meetings that most teams collapse into one. A deal review, where the conversation is about strategy on named opportunities and nobody says a number. A forecast submission, where every manager submits a written commit early in the period and it is logged so it can be graded later. And a variance review, where last period's called number is compared against the result and the misses are dissected by cause, not by person. The discipline that makes it work is that the forecast is submitted in writing before the discussion, so the room cannot anchor on the loudest voice. Underneath it all sits the operating cadence: the same meetings, the same order, every week, so the forecast is a routine output rather than a quarterly panic.