I'm considering releasing a cover song. I'm not sampling any previously recorded audio; I'm performing my own version of the song. However, I'm only covering the chorus, and adding my own verses. Is this still technically considered a cover? I know about licensing covers through Harry Fox, etc. but I'm not sure if this works the same way. Also, am I allowed to change the title from the original title of the song, or does it need to be the same? I'm hoping to release the song on iTunes, and I'm only expecting about 400-500 downloads... so my final question is, how much do these details matter? Thanks!