On a side note when a QB is less than 7 yards and tries to punt or quick from that formation he is not in a legal kick formation and roughing the kicker is basically null and void.
I think you're misapplying what you heard.
If a QB receives the snap, rolls out to the left, looks to run for the first down, but instead kicks the ball on the run, right before being tackled, this is NOT the same protection as a kicker who receives the ball in kick formation and clearly is going to kick the ball.
Much the same as that we allow a QB to get tackled JUST AFTER throwing a pass, if the contact is unavoidable. In this situation there is no flag for roughing the passer.
Similarly, if a player 'all of a sudden' becomes a kicker, when it was not apparent he was going to kick, the protection is similar to that of a passer. A late hit is definitely going to get a flag, but a hit JUST AFTER the kick was kicked, that is unavoidable, would not get the protection as a kicker normally would.
There is a case book play on this, I'll find it.