I'm just taking a wild guess here, but I believe that the functionality of this entire plugin is built solely on the usage of only two attributes at the very most. It just sets up a grid based on those two attributes. If you create a 3rd, such as what I'm assuming you're doing, despite it being somewhat detached (a random text attribute), it will cause this mod to haywire and behave unexpectedly. It will probably require some meticulous code editing to get this plugin to work within your requirements.