In your title, you say "dropped frames", but then you say "game will get choppy from time to time", do you just mean on stream, not the actual game while playing?
For dropped frames, you did have a few:
21:58:10: Number of b-frames dropped: 58 (0.029%), Number of p-frames dropped: 60 (0.03%), Total 118 (0.058%)
Though the number of dropped frames you had was totally insignificant, and something you could probably ignore. Still, if you wish to reduce it, I would recommend just dropping down the bitrate to about 3000.
