All change, be it positive or negative, an addition or a subtraction, has to make it through the Deadzone. For example, imagine I institute a new practice of morning meditation. The effects of the new practice will not be instantaneous—I will feel them only after a period of time. And it is this period, where effects are accumulating invisibly, that is the Deadzone.
The Deadzone could manifest as days, as weeks, as months, or even as years. The timescale can differ, but the fact is that every change, minor or major, needs time to take effect and for the consequences (or lack there of) to become apparent.