NC Rain/Actual rain discrepancy

I am currently seeing a discrepancy of 0.5 in between NC rain and my unit. It has been raining solid for about two hours. Anyone else see this with their station? It is not even close.

Do you mean between the NC value and the non-NC value for the same Tempest? If so, how long has your station been online? If not very long or not much rain since installation, the unit may still not be calibrated much yet.