Whenever your updated balances are reported they will be factored into a score. Scores are generated based on whatever data is currently in the report. You can use a CMS with daily pulls if you want to verify that the balances have reported before applying. If you have your statements then you can look at the statement dates. Most cards report on statement date. You can also call your creditors to verify when your accounts report. If you have a credit report you can look at the last reported date for your cards.
IIRC Chase will perform a midcycle update if you pay a card down to a 0 balance.
Keep in mind that there is a hit for having all your revolving accounts report 0 balances. That said, you can pay in full and have a balance report.
sl7450 wrote:Would my credit score increase sufficiently?
We can't tell you that. You can calculate the change to your revolving utilization. A significant improvement will lead to a bigger change than a smaller improvement but we can't tell you that you'll get X points for paying $Y.
sl7450 wrote:I'm afraid to apply for the Marriott Rewards Credit... fear of being denied and my credit score impacted...
The only hit would be the hard pull which has a relatively small impact. However, impact can be bigger for those with thin and poor credit profiles.