Don’t know if it would bother you but Bkool also doesn’t measure watts accurately. Most people report over reads between 10-40% on the Bkool pro. Does the spin bike have it’s own power meter? That could make a difference but I wouldn’t assume to rely on Bkool readings. Also if you did discover your unit was inaccurate a wouldn’t rely on Bkool to be honest in their responses.
I'm not certain how it derives power TBH.
According to the road c.c. review it's within 2-3% of the Garmin vector with no drift. It's reliable if not 100% accurate.
I really want to see a review by DCR.
A unit like this should in theory be better than a smart turbo with tyre contact. There's fewer variables and less heat produced by the components.
Tough choice.