Why does the Dashboard list more than one threshold?

Because your shipping zones ask for different amounts, and each shopper is shown the one for their own zone. The Dashboard lists them all, your store address's zone first and Rest of the world last, rather than one figure that would be wrong for somebody. The Setup screen describes the zone your store address is in, since WooCommerce puts shoppers there until they enter an address, and warns you if that zone has no free shipping.