Lets see what FEMA has to say about vents.
"Careful attention to compliance with the NFIP regulations for flood openings is important during design, plan review, construction, and inspection. Compliance influences both the vulnerability to flood damage and the cost of NFIP flood insurance. If openings are not compliant, the floor of the crawlspace or the floor of the enclosure becomes the “lowest floor.” In those cases, the result may be significantly higher flood insurance premiums, especially if the floor of the crawlspace or enclosure is more than a foot or two below the BFE."
Source:
https://www.fema.gov/media-library-data/20130726-1...
So again to my point "You might be able to lower your flood insurance by putting foundation flood vents on two walls of your basement, crawlspace or garage." LOMAs, grandfathering, and mitigation work are all site specific. There is no blanket answer. Talk to a Certified Flood Plain manager and an insurance agent. Preferably someone with both credentials.
@Anthony Lee
I am not really sure what you find misleading about the word "might". Perhaps you should look it up. I would also encourage you to start using spell check.