Congrats! Glad to see you got it working at 8x.
Actually, if you notice the first dip in writing speed in the graph for your "fake" drive, you'll notice that it coincides with the first jump that happened in the first graph above that was done on a "real" 812s.
I take this to mean that your drive tried to jump up to the next speed level, but it felt it would get a better burn continuing at the current speed for the moment, which is why it took a bit longer in total burn time.
I'm sure you'll get some burns on MCC004 that look exactly like the first graph, but on your drive.