Somebody has criticized
Mr. Fan's explanation earlier.
It's true that multiple I485's can add more workload at the very beginning. But USCIS will find out very soon that there has been a prior I485 for a person, and will update it instead of keeping multiple I485's for one person.
If anybody has got multple A#'s for their multiple I485's, then I would say that Mr. Fan's explanation could to some extend be right.