I'm a credit analyst.
Even if you clear 30k of debts in one full payment, it takes time for credit ratings to go back to normal. Takes at least 6 good months to see a major impact on those scores.
Also, the best credit behavior you can have to boost your scores is to pay in full everything you have at the end of every month. The fact that credit companies will report "better ratings" if you keep a balance and don't pay in full at the end of the month because they make interest money with you is a legend.
I know mortgage analysts like to see not only that you pay up everything at the end of the month but that you also don't have too many credit cards or personal lines of credit (revolving credit) active and ready to be used even if cleared up. So if you have a couple of cards, close a few of them.
Credit companies report nothing. Your credit ratings are calculated by a formula (and by a credit bureau ie: Equifax, Transunion etc...) that includes a lot of factors going from taking in account single credit checks (we call that hits) to the length of time your file was opened with all sort of details establishing differences between revolving credit/loans/open buy accounts etc...
The only thing the credit company reports is your balance at the end of the month and the fact/how many months you've been late.
edit: Also, if you know your credit scores are a bit low right now, avoid shopping around too much for your mortgage. Like I implied before, as soon as a bank or financial institution makes a credit verification, it hits your file and will impact your credit ratings. A couple of them is no biggie but a lot of time will show you as actively looking for credit (even for a home) which is not good if your goal is to bring back those scores to a decent rating.
