I think there were issues in the past that your couldn't apply the `:2' modifier to the track number, and your method would produce ``Velvet Underground - White Light, White Heat - 1 - White Light, White Heat.mp3'' rather than ``Velvet Underground - White Light, White Heat - 01 - White Light, White Heat.mp3'', which means that it would sort incorrectly on albums with more than 9 tracks.