Ok, did some more tests today. Found some more things about the iphone app and the differences between the Rega white and black belts.
First, the iphone app. Sometimes if you let the test tone run out to the end of the record or lift the needle while the app is running it can cause a large frequency spike or dip, which throws off your overall numbers. I think this is why my numbers were weird (thanks @Tonywinsc for noting this) showing the table running a little fast but the negative deviation being the largest, which didn't make sense. All the graphs for these weird numbers showed a large dip at the end of the measurement session. Since there is no stop measurement button on the app, I've found changing the preamp input is the best way to stop the app without any spike or dip.
So, with the white belt and changing the input source on the preamp after a good sample duration, I got the following numbers:
overall freq: 1001.8 Hz
filtered deviation:
-0.02% / +0.08%
-0.2 Hz / +0.8 Hz
And with the black belt today, I got:
overall freq: 1000.6 Hz
filtered deviation:
-0.02% / +0.03%
-0.2 Hz / +0.3 Hz
So, after reading about other experiencing larger deviations with the white belt, it seems I am seeing the same thing plus it makes the table run faster.
I'm keeping the black belt on for now. I have a $20 red belt on order from the UK after reading good things about it. Will post those test results when I get it.
Anyone want to buy a Rega white belt with not many hours on it (about 6 months of average play)? ;)