I'll take ownership as an early flagger. You ended the original post with something along the lines of "is this right?" or "am I missing something?", which requires a response, and an answer soliciting discussion is not an answer. Better to post the clean answer, and DV the original answer if you believe it to be incorrect. If you want to have a discussion about it, or are unsure, post it as a question and refer to the original.
Or, perhaps best for this particular case: a comment on the original answer saying "don't you mean 2(Vdd-Vc)?" would have been direct and to the point.