Difference between single and album songs

[+Etra]

Hellos.

I've been going through all my music and separating them by album / single / track / etc. and I noticed two of the songs on her "A" single sound totally different than the album counterparts (monochrome and too late.) The other two songs sound the same, though (End roll and Trauma.) So, I was wondering if there were any other songs that sound different than what the albums release?

In fact, after the Free & Easy single, she stops naming them "Free & Easy - original mix" and just does "Dearest" and what not.

Just wanted to make sure there were no more differences outside of monochrome and too late, since I don't want to be uploading the same exact song twice on my iPod. x.X

Thanks a bunch!