Richard, in an absolute sense you are correct. That's why I used the qualifier "relatively". The change in pinion angle in a typical 4 bar setup in very slight as you know. As I'm sure you're also aware, part of what you describe in the front double A arm arrangement is not transferable to a rear application as the front arms are not typically parallel to one another in either plane so that various factors like camber, caster, anti-dive, etc can be engineered in. On a solid rear axle those factors don't apply. Some anti-squat can be factored in by either dropping the front of the upper bars about an inch, or raising the front of the lowers that amount, (race car considerations excluded here), but the rear bars usually are nearly parallel fore to aft.