If you didn’t pair the separate sensor it would default to the Kickr (internally calculated ) cadence.
Edit: I should add that I have the Wahoo cadence sensor as well, the one that I attach to my shoe and it also tops out at about 180ish. When doing Cadence builds, I will use a Garmin cadence sensor that is attached to the crank and reports only using Ant+. It is with that sensor that I have retained my membership in the illustrious 200+ club.