Numerical Turn of Phrase

I enjoy numbers, and I enjoy reading even though I don't always enjoy reading about numbers because it can get very tedious. Nevertheless, occasionally someone puts chocolate in my peanut butter (or gets peanut butter on my chocolate), and you get something like this:

"Samia of Fife was five feet tall, exactly, and all sixty inches of her were in a state of quivering exasperation. She weighed one and a half pounds per inch and, at the moment, each of her ninety pounds represented sixteen ounces of solid anger."

I just enjoyed that line and thought it a great way to open a chapter and introduce a character. And two things occurred to me only as I type it: even though it's science fiction, the measurements are not in metric, and the weight of 90 pounds is given without any consideration for actual gravity of the planet. What would the Galactic Empire think?

Unfortunately, I was left scratching my head by a phrase used two pages later:

"... made her an object of mild derision to people who were accustomed to thinking of the aristocratic Ladies of Sark as devoted entirely to the glitter of polite society and, eventually, acting as incubators for at least, but no more than, two future Squires of Sark."

Now, since "at least" means no less than, what this sentence is saying is that ever "Lady" is expected to have no less than nor no more than two children. In other words, two children. Now, I'd want to call this guy some kind of hack, but since it was Isaac Asimov, most would likely disagree with me.

So, okay, so maybe "hack" is too strong, but it was still a weird way to say "two and only two", or simply "exactly two".