What is the deal when bands release "bonus tracks" on albums only in certain countries (e.g. Japan)? Also, it seems that bands record more songs than what makes it onto the final album. I understand if they want to split it up over more albums, but it seems also that some of these songs never get published. For example, "Dance Macabre" that never made it onto the first SX album. I've heard vague references from bands in interviews to "the label wanted ____", but what is exactly the deal here?