Table XI is the mobility table data, using flexometers and the mobility notation table (as well as other techniques). Table XIII is from the X-ray study. Look at page 50 and see what equipment they use for each sub-test. Subtest 2 (X-ray study) lists X-ray facilities and a mock-up of the couch as necessary equipment. They suit someone up, sit him in the couch, and X-ray him to determine the eye-heart angle, and measure the joint angles using the mid-points of the major bones. If that wasn't enough, you can infer he's seated by looking at what they measure. In the mobility table study, they measure (among others): hip adduction-abduction; hip flexion-extension; hip rotation; trunk rotation; trunk-hip flexion-extension; trunk-hip lateral flexion. In the X-ray study, the only one of these angles they measure is hip flexion. This conform's with what you'd expect if the subject was seated in a couch.
No. They are seated for the eye-heart angle test. You can't expand that to other tests, as you've done here. They don't say or suggest this. If they did, it would have stated so. But this was specific.
You can't make such faulty leaps of logic.
For the umpteenth time, did you have any evidence supporting your assertion that the suit couldn't bend at the knee as witnessed, or not?