the 12gb is most likely all the "old" or shall i say original audio loops

this DVD seems to be ONLY new stuff, OS4, new audio loops, new styles, new sounds etc..,

so in order to use this DVD you have to have OS3 installed,
because it ONLY adds to it

this is how I see it.

there's no way everything inside AUDYA is only 1.2 GB

but AJ/Ketron would know best.