My first thought was "why isn't that an exact value?", but I realized soon afterward that of course it's not exact, as any meter with a good continuity beeper uses analog circuitry to get a fast beep response, and that analog circuitry inherently has tolerances. So I understand why they give a range.
What I don't understand is why the range is so large. I would understand something like 30~60 Ω, but this is more than an order of magnitude! What is it that causes this extreme variation in the beeper threshold?
Is this sort of variance normal? What sort of circuit is typically used for this, and what makes it so sensitive to component tolerances? Is it even that sensitive to component tolerances?