New reloader, New Chrono, Help me make sense of the data.

[lordpaxman]

The chrono makes reloading much more interesting.

Indeed. As others have stated, your lower charges aren’t burning as well as near max. Your numbers looked entirely reasonable for what you were loading. The other thing to consider is powder position in your revolver, and I’m presuming you’re reloading .357 and not .38 special at this time. You may see increased ES and SDs just due to the fact your first shot may have the powder forward (nearer to the bullet) and then the others are wherever the recoil distributes it.
Kudos on shooting a factory load first to get an idea of the chrono’s setup. I do this and call it my “calibrate” string, just to confirm the chrono is working and numbers are “reasonable”. Depending on what you have and how much you want to spend, consider shooting a less expensive factory round like a .22 if your chrono can handle it.
I also shoot a separate target per load when I chrono and keep that as my precision and accuracy target to see how the load is grouping. It’s a bit more difficult with a shoot through chrono but not impossible. Good luck! (And welcome to the addiction).