Yea, it seems to me that handing an ME the individual tracks (tracks being considered seperate parts of a song here), or "stems" would be asking them, in a sense, to mix your song for you. I'm assuming an ME would go ahead and balance the song a little further with volume and pan settings that would be appropriate for how the ME plans on going about mastering the song in the long run, but would they go as far as processing individual tracks (used in the same context as above) with EQ, compression, etc. before even getting to the final stereo track mixdown? I mean how much work are clients asking the ME to do here?