Low offers are very common in insurance claims and may not always be the fault of the insurance company. A big part of the problem is that adjusters are not “adjusting” these losses. Because of the size of storms and the number of claims, “adjusters” are brought in from all over the United States to write repair estimates. A public adjuster should have knowledge about local pricing, or demand surge. Some adjusters might want to write an estimate and close the file, so they can get paid. It's important you work with a public adjuster you trust.
What happens is that the estimates are given to an inside claims manager who never saw your claim. They use the estimate (sometimes poorly documented) to determine your settlement offer. In property damage cases the adjuster should adjust the file in your presence so that you can come to an agreed price and scope of loss. If you are not getting satisfaction or the answers you need, you need to go to a more senior claims manager and demand a re-inspection with “your” adjuster present (if possible) so that they can have input in the pricing and scope of the loss. Be sure to keep a note of anyone you meet. If given instructions or promised some action from an insurance representative on your claim, document it or ask for a confirmation in writing.