The reason I asked is that I just wondered if there was any better way to do it. I chrono my own bows and arrows from time to time, just by shooting the arrows through my chrono at what I hope is a fairly consistent draw length, same as you do. My typical results through the chrono will vary within 5 fps usually, with the occasional arrow that goes outside of those parameters and I chalk up to a poor release or some chrono measurement error.
Ken Beck at Black Widow uses a shooting machine and a much more expensive chrono than I have, so his results are much more consistent, of course. But probably not as realistic, given that we shoot with our fingers and not with a machine.
Shooting my bows, which are in the same poundage range as yours, but which I draw to 27.5", I'm more likely to get readings in the 175 fps range. I don't know if the difference is about what you'd expect with a 1 inch less draw, due to differences in our chronos, or whether my release isn't as crisp as it should be. I've considered setting up some kind of rig to hold my bow so I could pull it back to my draw length with a release, so I could measure what the difference in arrow speed is, but other than curiousity I don't know how I would use that information, so I haven't done it yet.