In each generation, there are at least several remixes to a past generation song. For example, G/S/C/HG/SS' Kanto music is a remixed version of R/B/Y/FR/LG's Kanto music. Black 2/White 2 has all the Gym Leader/Champion themes to date, but all of them are remixed versions of the originals.
There are more, but I'll just stop here.
(I never understood the question really; I was just doing the best I could to answer it)