Problems with the phase_shift calibration

[jjtoard]

I tried to calibrate the phase shift but look to need a value outside the predefined range of 0-2
at 0 I get powerfactor of 0.96
at 1 I get powerfactor of 0.92
at 1.9 I get powerfactor of 0.89

So I tried 52 (shifting around 360° to get around the limit of 0) and I got a powerfactor of -1.12
with 49 I got a powerfactor of -0.96
But with these high values some other powerfactor for devices with a powerfactor of around 0.04 nog to 5.6

What am I'm doing wrong with this calibration ?
I used a 2000W electric heater so should be full resistive .