Hello Greg,
Great observation! You can't tell very well from the pictures, but the bevel is not the same angle, but on a "plane" that varies in pitch according to the height and width of the location on the stock. The profile and the widths are all established before making the "planes". It's part of a method for achieving good stock architecture that Jack Brooks teaches... I highly recommend taking one of his classes!
I used draw knives, spoke-shaves, planes and rasps in shaping the stock, primarily a plane when it worked well. It depends on the grain, and if I can get a plane in to cut due to the changing angles on the stock and the size of my planes, hopefully that makes sense to you. I often use a rasp in the tight spots, or when the wood wants to get chippy.
Curtis