RULE 1: The balance on an account the day after the Statement Closing Date is the amount that will be reported to the Credit Bureaus for that period. It may take a couple weeks to show up on your credit report, but that is where it comes from.
RULE 2: If the balance is over 30% of the credit line (limit) it will negatively affect your credit score. And the closer you get to maxing out, or nearing the limit, the worse it is. I've seen an 85-point improvement taking one account from 93% to 25% in one-month.