Hi Steven. First of all ... to get the best help possible ... post this on the Historicus Forma site. Eventhough this forum is for AFV figures, where sculpting is concerned, you´ll get the best help on the other site. You can post on both as well, so its still not too late. There is a few guys on HF who are professional sculpters and have a great eye for these things.
Personally .... I dont have a clear picture in my head of how this uniform should look, (how bulky or tight it would be on the arm) but it appears that the distance between shoulder and elbow is a little short, and maybe the bicep should have been more pronounced as ´the figure is stretching his arm forward. The crease detail on the arm inside (pic 1) looks good, but on the back side of the arm (triceps, elbow) there are almost no creases and no arm shape ... the bent elbow detail does not show through. These details could be void, if you have a decent reference picture that shows this is how the blouse is, but sometimes its worth taking a little artistic license to make it what the eye, thinks it should see. Such details will also make painting this guy afterwards easier.
What material have you used .... it looks like a nice smooth finish.