Further down in the same transcripts:
Pilot: we're in a rut. Well he seems to want those back steps down. Well, we've kind of convinced him now that we can't takeoff with them in ground position. But he wants them down when we get airborne, fly with it down and then so he can bail out at any time, I don't know..
Ground: what's he want down.
Pilot: back steps.
Ground: no, you can't do that...
Pilot: were talking to Paul and he says we got a plan how we can get them down..
Cooper clearly demanded the airstairs lowered in flight initially.. "aft stairs to be lowered after take off"
LATER,,
The context for airstairs down on take off.. (this context may be debatable)
After the discussion about the stews "trying to get him to let us lower stairs partially for takeoff"
AND
After the discussion about the fuel range and another destination.
My point is that Cooper's
initial demand was "airstairs lowered in flight" it isn't clear who or why the later discussion about airstairs lowered on take off was initiated. I believe he discussed lowering before take off either to allow Tina off the plane or because they were discussing the new destination.
The common narrative has been wrong.. His initial demand was NOT take off with airstairs lowered.
.