Commercial auto question: A prospect has a Ford Transit titled to his...

Commercial auto question: A prospect has a Ford Transit titled to his business and himself personally. Presently it’s insured with a different agent on a personal auto policy with Auto Owners. My underwriter is saying that it must be on a commercial auto policy. The client is a handyman/carpenter, sole proprietor. I don’t have an AutoOwners contract, would they likely allow it to be written this way? Other carriers? The personal/business titling of the vehicle is ma