In 2013 the new IRS rates have a 0.5 cents resolution. 

How to take advantage or the 55.5 cent ? 

In order to add this half cent per mile such as 55.5 or 56.5, you will need the latest software revision.

Please download and install the latest version of the software from the download section.

2014 Standard Mileage Rates,-Medical-and-Moving-Announced

Standard Mileage Rates for 2013,-Medical-and-Moving