Considering that the information in that thread suggest that X on UA is both economy award and F upgrade inventory I'm pretty comfortable in my belief that it is at least somewhat askew. Oh, and there's the part in that thread that states quite clearly, "If looking on a CRS or via other carriers, you still need to look/book O I and X (Star Standard) classes for UA rewards." Since the OP is looking for CO upgrades they are going to be using the standard classes and need to be looking at what is exposed to partners. That's why using the ANA data is most reliable for them.
Care to disagree further?
Not so much in picking up on sarcasm, huh?