The Second Brigade was the Federal right flank. Davis intended to outflank the Confederates by moving the First Brigade past his right & then having them move north. There was a battery in the field to the west of the Second Brigade's position. So, if I read your explanation correctly, by having the Second Brigade do a backwards right wheel, he was creating a gap between the Second Brigade & the next regiment in line, exposing both the battery and that regiment's right flank. The forward left wheel would have placed the First Brigade between the attacking Confederate Brigade & the main Confederate line. Finally, he would have made it impossible for the Federal artillery to fire without hitting their own men.
It seems to me that the maneuver would have made a lot more sense if he had ordered the Second Brigade to "fall back in changed front to rear on its left". That way, he would have refused his right flank (in a manner of speaking) and protected the battery (although he would have effectively masked it).
Am I interpreting this correctly?
Again thanks for the info.