Speaker height...should known better

The other day I was listening to my system sitting down on my chair on my computer when all of sudden I had lower my head to glimpse a song on my screen when I realize, wait this sound much better. I have only lowered my head a few inches or 3 and all of sudden the music sounded way better. So much better to a point where it sounded coherent, phase timed and much more dynamic. I thought for a long time I have placed my Triangle BR03 tweeter at ear level. From the perception view from the listening position I would if thought it was at ear level. I was wrong. Currently my ears level is 3 inches above the tweeter(about the top of the cabinet). When I bought the speakers stands a few years ago, I got them new for my other speakers that were smaller. The current height on the stands are 28". I think what need now are at least 31". No wonder my measurements had a gradual roll off of the high end at around 8k at a couple of speakers I had. Now I am planning on getting higher stands to hear the difference.