So what happens when a song like...say...Inside Out by Nick Gallant, a song with only 54 registered scores according to Keldon, makes the console jump and doesn't sell? Who eats the costs? SONY? HMX? The chart submitter? The band?
Five a week may not seem like very much. It might even seem unfair. But it does see the songs most likely to make the cost of submission in return. By not pumping song after song through SONY, it potentially gives older, poorer performing songs a chance to catch on.
Ultimately? You want to see a particular song? Work harder to get the word out. There are nearly five hundred songs available. Not everything is going to make it, unfortunately.