I just don't see the point. Put it like this...

DJ / Producer 'X' starts up a new label, 'X' Records. The first lot of releases are wicked, really solid acid techno / techno. Things are going well. A few months on DJ / Producer 'X' starts another label thats pretty much the same quality tunes, but on a sub label 'Y' Records.

And this 'Y' Records being the one that makes me think WHY? :?:

Why not carry on with 'X' Records? Keep the quality releases coming out on that label. Is there really any need for another label when the styles on 'X' & 'Y' Records are pretty much sounding the same?

I personally, don't think so...