In order to guage a song, the station plays a song a number of times and then polls audience. Certain stores on Soundscan are weighted. Sales at Newbury Comics equals 12 sales in a big store. BDS - a song needs to be registered with each specific format. AAA is a softer sound, the emphasis is on quality.
Some labels work a record for a year.
Boston is one of the best markets to break a record. As Good As Dead broke in Boston after 8 months, and a year and a half later in their home territory of Chicago. A great song will always get played. Rent a van before buying. Buy food at grocery stores instead of truck stops.