Just tried workout mode with a Bkool Classic (latest firmware with ANT+ FE-C).
When the system set the ergo resistance on the trainer, the output displayed was about 20% higher than that demanded - even dropping gears or cadence, the resistance would maintain an output of around 15%-25% higher than needed.
It certainly felt like the output was what was being displayed - it hurt! If I stopped pedalling, the system would take it out of ergo mode for that segment - so I could complete it by trying to match the requirement through gears and cadence - but having to stop first for about 30 seconds killed off any change of sticking to workout intervals.
If it’s of any help, TrainerRoad are having a similar issue the the Bkool Classic and Pro running resistance higher than demanded - so it sounds like it could be an issue with the Bkool spec they are publishing.