As a small business owner with a lot on your plate, the last thing you need is to make any tax filing mistakes that could bring the IRS to your doorstep.  Often getting audited by the IRS isn’t always the result of intentional acts. Here are five of the most common tax filing mistakes that are likely to get you a dreaded letter from the IRS asking for more information: 1. Under-Reporting Income Whether you are a freelancer, a brick-and-mortar…