I didn't notice this before. I've heard Bugliosi say this as fact (the 14cm measurement) and when he did it sounded convincing until i read your post.
Bugliosi would say whatever he thought the government wanted him to say.
The autopsy face sheet was marked "verified." 14 cm below the right mastoid process is not even close to Boswell's mark for the back wound. Boswell stood by every other drawing and mark on the face sheet, but he claimed he goofed when he made the back-wound dot. So every other mark and drawing he made on the face sheet accurate except the back-wound dot. How convenient.