RE: To high of a pitch with power bugle
I put teeth on upper side, and use lower lip to vary pressure on band. Pressure on band has most to do with pitch. BUT! Which band are you using? They have white (regular) and gray "Hi-pitch" bands. I use the white almost exclusively.
You can also get pitch difference by sliding band towards hole (higher) or away from hole (lower pitch).
Did you ever play sax or clarinet? It is very much the same as you need to develop your embouchure. Try this, place mouthpiece in mouth and without trying to make any elk calls, vary the lip pressure on the band so as to start low and slowly move note higher. Capice? Then try playing a familiar tune by varying pressure on band. You know, happy birthday or something.
So to get lower notes you need to use white band, slide band back, loosen pressure on band, and even kind of drop your jaw as you do lower pressure. Then start growling in your throat as you "make music". You'll like the results.
Remember, what you say in response to an elk is more important than you think. Saying less is sometimes saying more!