You do realize that Cecil’s article covers 3 theories, the second of which (working backwards from crucifixion date to conception date) is the one in your cited article, don’t you? Hardly a strike-out.
It seems more the probability of what he mocked as mere cocktail chatter giggles, while not having a Scriptural reference, is likely the real McCoy based on how the early Church did its figuring. This was based on so-called “integral” ages of great prophets and was tradition. It is far from likely (his third claim) that Christian church fathers merely appropriated an existing pagan event. Which is the common claim that appears to be the incorrect one.