I noticed alot of your stuff is 16#. I dont know of many people around here that throw 16# anymore. There is no difference between 15# and 16# balls in the opinion of many bowlers. Thats extra weight may be the reason you tire so easily. Another thing is that you shoud be paying attention to the reaction of the pins when you do strike. If you feel you threw a good shot and barely struck its time to move. On a house shot that move is usually 2 left with your feet and 1 left with your eyes. Every little thing helps.