I found that it goes like this:

- Right click and hold will axis the formation on the left flank

- if you Right click and hold and THEN press ALT it will pivot around an axis in the center of the formation - not where you told them to go, but back where your troops are presently located

- if you let go of the ALT key while you are doing all of this they will just face where you thought you told them to go.

It's all very confusing but yes, I can confirm this.