In my EH product, I am trying to validate our QRDA III generation for CMS108v8. CMS108v8_TestDeck.zip contains a patient that qualifies for the denominator and the denominator exclusion. 

When I upload CMS108v8_PerformanceRate_NA.xml, which has a performance rate of nullFlavor="NA", the error given is "Reported Performance Rate for Numerator 73A59A09-B8A3-46FE-AE6B-BA2E5A8445CD should not be NA". 

When I upload CMS108v8_PerformanceRate_Zero.xml, which has a performance rate of value="0", the error given is "Reported Performance Rate for Numerator 73A59A09-B8A3-46FE-AE6B-BA2E5A8445CD should be NA".

There is no error if I remove the Performance Rate element altogether, but I do not see why this is the case.