The point is, I don't care what the "real" length is, I prefer the buffer time, most the time. If there was a way to toggle OR show both, that would be the best of both worlds!
It's not a buffer time. It's the end time of the current stream segment which just means it will fetch another segment and add that to the current end time. Streams are often broken up into chunks and it's just showing you how close you are to the end of the current chunk.