Having a business and making cash deposits is likely one of the easiest ways to get a permit in MD. The permit will be restricted to while doing business, making deposits, etc.
I got mine based on being a retired LEO, but my business partner easily got one based on the firearms business. As I recall they asked him to prove bank deposits for the previous six month period, no dollar amount as specified by MSP.
They were MUCH more concerned with the bank deposits than transporting guns.
Cash deposits are not required per COMAR. The MSP has been trying to change their procedures to make it more and more difficult and making up new rules as they see us growing in numbers applying. The nice thing about an FFL is that you can get the restriction to also allow while transporting firearms or something to that effect. I am not an FFL, just providing some input.