But the spin-off issue probably impacted the decision. And the billing issues probably would have been worked out by Lorimar (as opposed to Jacobs).
And it worked out well for DALLAS (and the fact that the senior cast members, BBG and Jim Davis, came first alphabetically, was a nice fortuitous element). So they used it for KNOTS.
Also, DALLAS was about, primarily, a nuclear family. Eldest first just sits better. KNOTS was about a community, and familial status didn't seem to matter.
And, obviously, it keeps the agents at bay. Over on Lorimar-less DYNASTY, Catherine Oxenberg's reps were asking for all sorts of nutsy stuff which wasn't realistic, leading to her expulsion in 1986.