I guess one question I have re the first study you posted is: just because you get a certified LCA for level 1 or 2, does that mean the employer is going to actually pay what corresponds to a level 1 or level 2 wage? Isn't that the floor? LCA happens before I-129, so the employer is just certifying they need someone, anyone, to take the role.

For instance, a promotion or regular pay raise doesn't trigger a new LCA. That only happens when you change employers. As an employer, if it didn't affect the likelihood of an approved LCA (and the article does itself state that they're largely pro forma, and won't get denied unless there's an obvious error) why would the employer not pick the lowest class to maximize flexibility?