Wow, very cool, thanks wpoll and andrewwynn.
That QSilver7 document explains everything.

Interesting what I found on my (actually my wife's) X5.
Running the test with the car not running: 17 13.1 20.1 -> TYPO should be 17 3.1 20.1
After idling for about 3 minutes: 15.9 4.2 20.1
The the right tank value keeps dropping until it settles at: 16.6 3.5 20.1

I wonder why the gas was going back to the left tank after engine stops? Since gas is being pumped out of the right tank to be consumed with any over flow going back to the left tank, I would have thought after the engine stops, the right tank should rise from siphoning. I must be missing something here?

The good think for me is that the fix is working.