Haven't found the discussion re TWA 841 so my comment here may simply be repetition. I was flying for a B727 operator at the time and the word on the street was that the crew initiated a well known practice for improving performance at altitude by disabling the LE devices, (by pulling the LE Devices CB), and extending the TE flap to the '1' position, as this involved the TE flap only moving horizontally out, thus increasing the wing area. It was my understanding that this was a well known unofficial practice among the B727 fraternity. In the case of TWA 841 it is believed the wrong CB was pulled, the TE flaps stayed in and the LE devices deployed, jet upset followed.
If this post is all wrong or irrelevant I will delete.