Tomato Sauce Processing order

I'm looking for clarification on tomato processing. Many of the safe recipes call for cooking and crushing the tomatoes a few at a time in a large pot, then straining, then cooking down for consistency.

I'm hearing talk about freezing tomatoes. Is this order still an acceptable process?

-Freeze tomatoes -Thaw tomatoes -Run through mill/sieve -Cook and reduce to sauce texture.

My biggest concern is this requires only one round of cooking and I'm not sure if that is acceptable or not.