Something you might want to consider....
The gray values that come out on the empeg screen aren't evenly distributed. I've noticed your logos have the color reduction done in such a way as to depend upon the two middle shades of gray being pretty far apart. For example, the Z06 logo has values of 0 134 189 255, whereas the actual values presented on the empeg screen are closer to 0 80 96 255.
The result is that you're probably loading the logos onto the player and wondering why they don't look as good on the empeg screen as they do in GIF format.
What control do you have over the color reduction palette in your software?
Then again, if you like the way these are coming out, more power to ya.