I don't really see a problem with having a couple of hours of interval music and backing tracks duplicated and labeled differently for situations where different mixers would be accommodating my iPad,
So you just want to do extra work? I don't. And now that we have trims, there's no reason. If you still want to, though, by all means, go ahead.
I have no need to mess about, just trying to help you , I use a mixer that can cope with the output level of my ipad, as for the work you mention, for Goodness sake, to tag a few Mp3s and reduce the level, well that's an hour you will never get back but not the end of the world unless you only have an hour to live
