yeah you are not shifting your weight. you just stand there at the end of your throw, and don't really let your body continue to rotate(you can hurt your right knee doing that). Be natural after the throw, don't stop yourself. Ask anyone I have played with, I fall down in front of the tee 2-3 times a round because my weight is shifted out over the disc and in front of me. I fully commit to the throw and let my body flow. you really aren't getting anything from your waist down.
The one thing that held me back was going out to the practice field and focusing on how far my disc went. The practice field is not about distance, it is about technique. During every throw it looked like your head was focused on how far you were throwing. Focus on shifting weight, delaying the hit, and following through. You will see better distance in the long run.
Omega - QMS - MD2 - QJLS - OLF/S - DD - Scorpius
Tell me and I'll forget; Show me and I may remember; Involve me and I'll understand