Will, as I stated in the thread the discussed topic appears to address how the 30 day waiting period will be handled based on the presentment of payment, but the presentment of payment to the agent is not present of payment to the NFIP, therefore coverage does not begin until 12:01 AM of the day after they, not the agent, received the application and premium. If the agent waits 4 or 5 days before sending in the application and premium it is possible the NFIP will not receive them within the required 10 days and then you have a problem with the effective date being after the loan date.
This is a risk for you to decide if you want to take, but one I would consider carefully due to the CMPs given for flood violations and the scrutiny that flood compliance gets. It would only take a couple of foul ups to get assessed penalties.
The opinions expressed are mine and they are not to be taken as legal advice.