Pretty sure it's not the origin of the glass the matters, it's the coatings. And if they're grinding it in house in the US, then it's US coatings, so better than Chinese, not as good as Japanese or German.
Cheers. That's a handy link.Not entirely true. How they make the glass matters about as much as what they coat it with, and don't forget to throw in the importance of lens shape too. Here's a really basic article about it that I keep handy for people who aren't new but are looking to upgrade from bargain optics. It's a few years old so...
Optics 101: The science of glass