Earlier quoted context omitted.
No, the parent post is talking about the distance to the main land...
Maybe I'm not understanding? But my point is in both cases - unless there is really huge news I missed - both China and the US did not enter actual territorial waters with military vessels. The US transits the strait so China's large claims don't have legitimacy. It'd be like the us claiming any ships sailing around cuba are in our waters.
As for how long is the actual distance, well, that doesn't matter much.