What he said and your reach back is at eye height then the arm drops to below pecs and on some throws the arm rises from there and on others not. Nose up releases so pushing the wrist down could help. Also your follow through with the arm is short and more of it adds power. Engaging hips and shoulders and quickly turning the thumb down by rotating the arm counter clockwise right after the rip will extend the arm swing in the follow through. Weird as it sounds extending the follow through adds power and distance to the throw.
Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.