I was not saying that it states so specificly in the rules, but I know that was the way we were supposed to playtest them, and we just kept on with that wayof playing afterwards.
I have seen extreme "running around to get positioning on a possible Advance", so we just stuck to the move direct forward for those units NOT making frontal contact (as per your quote), to also "move direct forward" and switch orientation.
So, NOT (the) rule, but a common sense rules interpretation to avoid possible exploitation
