Why are the Pro Drums charted incorrectly in some early Rock Band Network songs?

The Rock Band Network launched before the announcement of Pro Drums in Rock Band 3, and we didn't know for sure at that time how Pro Drums and the Rock Band Network would interact in Rock Band 3. As soon as we had this information available, we released it to the Rock Band Network authoring community, but at that point, a number of songs had already been released with incorrect Pro Drum charts. It was also impossible to check Pro Drum charts at that time, since Rock Band 2 did not display Pro Drums. As a result, some early songs have incorrect Pro Drum charts, but all Rock Band Network songs published since 3/15/2011 and many songs published before that date have correct Pro Drum charts.