The orientation of the glyphs indeed suggests they were not painted in situ because AEs did not present vertical inscriptions rotated 90 degrees clockwise.
Your rendering of the glyphs in the first image in your post is indeed the way it ought to have been written if done in situ, but then the orientation of your cartouche is inverted - the horizontal line would come after his name and not before.
The horizontal line at the end of the 'chwfw' cartouche is positioned correctly in the Campbell's Chamber because of the orientation of the glyphs: read towards the faces.
However, I agree that vertical inscriptions were never written at a 90 clockwise rotation. It suggests to me that it is a lateral quarry mark and the stone itself was later positioned 90 degrees clockwise - the men at the quarry miles away would have had no idea of the position of the stone, only its size. This is perhaps why it looks odd to the modern eye.