It took me a while to narrow the problem down but after hours of trying different things, I have come to the conclusion that (on my form at least) when using the Quantity Field with Enhanced User Interface option enabled, it breaks my form pricing calculations on woocommerce.
I should note that the field is set to Drop Down and Required. (tried turning off required, no luck)
Interestingly enough, when I disable it and refresh the product page that I am using the form on, the calculations work again. Perhaps someone can look into this at GF? Thanks.