The ass-o-meter patent shows the need to elevate your feet to make an angle between your upright trunk and your upper leg roughly simulating your seating position on the saddle (~30° - 45° for aero, ~40° - 75° for more upright). Your sitbone distance will vary depending on the angle as shown on the patent drawing. And, yes, you get two small, distinct impressions from the sitbones; the distance between them is easily measured.
