Authors do sometimes disagree on what is what, but it could possibly be also due to the blending of Eastern Medicine or TCM, Traditional Oriental Medicine, with Western Medicine. There is some overlap in both, but there are some areas of both forms of medicine which are different from each other.
At any rate the thing I love about acupressure is that anyone can do it, and no needles are required. And I loved the idea that by pressing on the small toe, near the toenail, one could, if all works as the book described, turn a breech-presentation baby around in time for delivery.