For those keeping count, tonight is the 400th edition of this series – but who, outside of Fox, is keeping track? The real thing to track here is that this is the first finalist elimination edition of 2012, when one of the Top 13 will be sent packing. And they’re be sent to the tune of (and performance by) former Idol winner Scotty McCreery, who provides this season’s musical swan song for the departing contestants.