The 30 days is revolving. Once you determined (at 2nd verification) that there was a change, the bank has 30 days to deny.
Completed application means everything the bank needs to make a decision. If the credit bureau is bad, it's 30 days from receipt. Next step - appraisal, if that is low, 30 days from its receipt - keep going until closing, or a reason to stop.
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Integrity. With it, nothing else matters. Without it, nothing else matters.