I asked if it was really necessary and they said they had to. So perhaps this was a situation where they expected much more fraud if they didn't give me a new account.
I discovered it is a real hassle to change a business operating account number. Providers who, in the past, were happy to start doing ACH through your account with minimal documentation require a lot more to change that ACH account number. In one case, they asked for something I don't think I can provide (a scan of a canceled check) as the bank doesn't send those anymore. I'll have to see if they really only need a void check.
I discovered it is a real hassle to change a business operating account number. Providers who, in the past, were happy to start doing ACH through your account with minimal documentation require a lot more to change that ACH account number. In one case, they asked for something I don't think I can provide (a scan of a canceled check) as the bank doesn't send those anymore. I'll have to see if they really only need a void check.