Business address

I have a business address that is different than my home address but it is not an office. I just use it to get mail and it's my legal address. I assume the money I pay for that is not rent and I would not include it on line 20 on the Profit or Loss Form on Schedule C when trying to estimate my taxes? Similarly, I assume my mileage would be calculated based on my home address and not the business address since I do not have an office there?