There are two popular misconceptions about the passenger lists, First of all, they were created "...on the ship ... on the way over...by the shipping company personnel.." and NOT by some US government clerk at Ellis Island.
Misconception #2 is that only steerage were listed."All passengers, no matter 1st, 2nd or steerage, were listed on the ship's manifest.They normally put all first class together, then all 2nd class on another page(s), then all steerage on still other pages."
Interestingly there are US citizens who were making vacation or business trips that are also integrated with the new arrivals.
If they were US citizens or 1st class, they MIGHT not have made the trip from their ship to Ellis Island but went directly to the New York dock.