I can tell you that I often do them different than the way they were done originally. That is because the lyric speaks to me differently, and then I, and the folks in my band, add the music that we think gets the message across. I would never ask the original writer (if alive) to bless the song as s/he probably wrote it exactly as they intended it to come out. I am arranging on the basis of what I hear. Occasionally, I hear an arrangement that, in my mind, is perfect and I will use it, giving credit for the arrangement and the author. Always give appropriate credit to the author. More often I will hear an arrangement that serves as a "jumping off" point for me, but when it is done it will have various changes. I always credit the arrangement I started with in those cases as well.

Mick