Hydra humidifer question

Hey guys, Just wondering if anyone uses the hydra system in their humidors. I set the humidity setting by using the +/- settings next to the lcd screen to 67%, but I don't have a firm understanding of how to calibrate the digital readout.
Also,
as the system runs, the screen displays 2 readouts which I don't understand what they are. one says 73% and the second reading reads 64%.
The credo digital hygrometer is calibrated correctly and reads 67% which is where I want this cabniet to be at.
Any help would be appreciated.
Thanks,
Derek