Total posts : 45366
Here is a possibility. You said the voltage across 50 ohms was 6V p-p. That was for the unmodulated carrier. Correct?
In your first picture above, http://i6.photobucket.com/albums/y235/perryW/THonRealScope.jpg, I can’t see the switch, but I’m guessing it is set for 2V per division. If that’s the case, then even in the first picture, the modulation is well over 100%. I think the peaks at the bottom of the screen are flattened at 6 volts below the zero-mod point due to over modulation. With heavy over modulation, the asymmetry is fairly meaningless because it depends on the bias point of the modulator circuit.
You should try reducing the audio level substantially to see if that flattening goes away.