Oh gosh - you can keep re-reading these rules sometimes and still not be sure.
I agree, the 180 is a change of direction not formation. As part of a move therefore it can be used as part of a change of formation. The wording "Unless expanding from a column" in the second paragraph, IMO, reinforces this.
As you say you cannot turn 180 and expand from a column because of the exclusion stated at the beginning of the 2nd para and under the Expanding from a column bullet it states "The front element remains stationary."
Now here is where I'm firmly on the fence.
In the 2nd bullet Contracting or turning 90 into a single column, it states that "the future front element of the column either moves forward or pivots 90 ..."
So turning 180 and and then moving off to form a column is not part of those two situations. On the other hand it also does not specifically exclude other manoeuvres first either.
So is the 2nd bullet exclusive, is that the only manoeuvre that can be made before forming a column or can other manoeuvres be made prior to it?
I think it is open to interpretation.
EDIT
Since posting the above I also posed the question on our New Zealand facebook forum. 3 experienced players have responded so far all agreeing that you can do a 180 and then move off in column. The reasoning being that the 2nd para states "... a group move can include only these changes in direction" with the emphasis on the word INCLUDE. So the change in formation can include a change in direction first.