I used .5, .6, and .8. The .8 had the most lines, but was off by up to 30-seconds timewise. It wasn't a good test movie as there was a lot of mumbling. I'm going to try something else a little clearer.
That's odd. I just tried processing a file at .6 then .2, and the .2 gave more lines. One would think if it is a detection threshold for audio, the lower number would catch more.

