Ok after finally receiving help to straighten out my body.  I now have a good form and timing plus i have always had a nice release.  My problem is that with the proper form i'm having trouble with knee bend and keeping my arm straight.  It stays straight until right as i throw the ball it cocks or bends.  After being told of this i can tell that i do it and would like to correct it so i can have a better pendulum swing and less effort (muscle) to get the same shot.  If it helps i'm using a 4 step approach, slide somewhat, and am a stroker.  I can practice with the arm straight and sometimes get the desired shot but have a very hard time keeping it accurate.  These problems come from my double jointed-ness if i fully straighten my arm during the swing my elbow twist easily while my fore-arm and wrist are still in the same spot.  Any ideas or drills?  I'm pretty sure i can get the double-jointness out with prac. and the help of muscle memory.  Thanks