The mouthpiece that you're using doesn't have to do with this problem. When I first started horn (I'm almost done with my music performance degree now), I had the opposite problem: I placed the mouthpiece WAY too low on my lips. I emailed a million different teachers, and in the end the consensus was that I had to change it. However, different embouchures work for different people. I've seen amazing players with sideways, crooked, and completely wrong looking embouchures.

I'd suggest seeing a private teacher in your area and see what he/she thinks. It's hard to say over the internet, because I can't tell if the mouthpiece placement is negatively affecting your tone, range, intonation, etc. Another thing you could do if you don't want to see a local teacher is record a video of yourself playing and post it to YouTube. Feel free to email it to me if you want my opinion!

My youtube screenname is bttrflylkis.

Good luck!