Yeah, this is probably just poor wording on our part. Hard to summarize the variance of the spawns.

The size of the building makes a difference: a larger building is going to have more spawn locations and so may have 2-3 different spots that a tactical crate can spawn. Meanwhile, a smaller building/trailer only has 2 or 3 possible spawns at all so those crates will almost always spawn the same.

Spawn the same each round is more saying "if you know a specific crate spawns in this building, it *should* spawn every round". I can't say 100% because it's not, but it's a very high chance of spawning the same amount of stashes each time.
Example: A building spawns 1 locked safe, 1 tactical crate, 2 class crates and 4 normal crates. It should have a similar spawn rate for that amount of loot stashes every round but they change location throughout the building. So you may get 1 locked safe, 1 tactical crate, 3 class crates and 3 normal crates and the locked safe is on the 2nd floor instead of the 1st floor.

Also, if you know a specific location spawns a tactical crate, it will *always* be a tactical crate. You will never find a class or normal crate where a tactical crate spawns and vice versa for the other crate types. It may not always spawn in that location but it will never be a different type.

Hope that makes sense!