audiosens OPYou were probably on axis to the tweeter behind the chair and off axis in the chair.
I was just walking behind my sweet spot chair, and I had noticed that I can hear more of the high frequency
Also use a mirror get your better half to go along the side walls with it against the wall till you see the tweeter in the reflection from your listening chair. Mark those spots on either side and hang something thick and soft there, to stop any secondary tweeter reflections which smear the highs reaching your ear.
You can also do the ceiling (and floor if hard surface) if your up to it.
Cheers George