As an H1B employee, I can assure you that the amount on my LCA was the same as I was paid. That said, it is important that people understand what these figures are - they are not actual technically salaries.
The Wikipedia article probably does a better job than I do, but the LCA is a company submitting what they plan to pay an employee when they hire them. As far as I am aware, if I get a pay rise the company does not need to resubmit an LCA.
Can you explain?