Good advice above...... You do seem under spined to me..... I shoot 2016's with a 47# bow and I'm a tad under spined..... Have you bare shafted those arrows? The spine range on those are 50-55 at 28..... You're shooting 30 inches...... I believe 2018's would be a better fit.... BUT, other things can effect spine, so if you are grouping your bare shafts with your fletched shafts, I wouldn't worry about it......

If you can afford it, get Rick McKinney's book The Simple Art of Winning...... It has some good chapters in there about back tension and the release.... I'm working on mine right now as well..... I noticed it getting very sloppy here lately.....