The Annual Threshold is the total the scheme expects you to spend on day-to-day care (MSA plus self-payment gap combined) before triggering Above Threshold Benefit. It's a per-beneficiary figure, set annually by each plan, and resets every January.
SA example: Discovery Classic Comprehensive: main member threshold is R34,810. Your R29,550 MSA gets you most of the way, then a R5,260 self-payment gap completes it, then ATB takes over for the rest of the year.