Even by your own metrics it demonstrates that conception dates, unless you had sex once during your ovulation cycle, are largely inaccurate. You example of growth, although is a thing they do is still inaccurate. You might just have a big baby or one developing faster than normal. That being said, of the exact date was known how on the fuck does it take over 6 weeks before you start doing something about it.
In at least one pregnancy ok aware of the woman knew her date of conception and was told "It doesn't work that way."
To your point, we'll more than likely never know if the story is true. That's the fun thing about stories that can't be verified, you get to just out them out in the world with no downside.
Granted, that story also suggests that in Ohio there's some child rapist running around who didn't make the news.