Elite Qubo Turbo power accuracy

Hi. I’m a relatively new cyclist and Zwifter. Im using and Elite Qubo Power B+ Smart turbo and I’m not sure if it’s putting out the correct power output. I’m fairly fit (triathlon) yet when it got up to 150watts on Alp Du Zwift, I almost couldn’t push the pedal down (I’m 60kg). On the lowest gear, I was putting out 120watts but couldn’t get above 70rpm. I could be rubbish at hills, but is there any way I can check? Guidance on this turbo / subject is quite complex for a newbie (P1, 2 and 3 values!?) so simple is good. Thanks.