I had the PRS-29a and mine was pretty much as you described. Have had a couple other watches with the same movement and each one wound a little different, or at least it felt as though they did. I believe it has something to do with the size of the crown. I know it sounds weird but I believe it to be true. I cant say as to why there is such a difference between your PRS-29a and 29am because they are essentially the same watch, just different dial and hands.