There was a thread on FB thus week with a couple of people noting that their kickr was under reporting power compared to their power meters. So much so that with PM would place the rider high in B but with his kickr he was having to race C
If I recall another rider was seeing the same, whilst a third was ok.
There will always be the odd unit not functioning within +/- 2% that the Kickr and other top end smart trainers are designed to. I can and have checked my Kickr against my Stages Power Meter. I had last year where there was about 20Watts difference. I did a spin down calibration and then each reading was with 10W.
The new Kickr firmware has further improved reliability of power reading by disabling the sensitive strain gauge and use magnetic forces to read power from the electronic brake.
It's pretty futile to say the Bkool Pro is a consistent reliable trainer to display accurate power. There are too many examples just within our own small group. Carl, I suggest you seek out the use of recognised power based trainer or separate power meter. Do a back to back ride and see the difference.