I change my bass height all the time depending on what is more comfortable at that moment, primarily for health/muscle/joint reasons but sometimes for the style of the music I am playing. In an ideal world I would spend more time in a slightly higher position as I find that I get a slightly better tone on fingerstyle playing that way on average (easier to strike the string from a better angle), but right now a lower position tends to be more comfortable for me for various physical reasons.