So essentially, I would get a certain amount of tokens. That's locked in at time I make the purchase. So if I bought 2 ETH worth to get 2000 tokens, it's still 2 ETH and 2000 tokens no matter what.

What I'm confusing myself with is the exchange, which in general is relevant but not necessarily right here. I guess I'm speaking out loud and answering my own question now. That makes sense as the number of tokens is the same it's just the price of ETH vs USD that is fluctuating.