Eric,  +1    In addition to repeatability, I would also add that the sport league forced me to learn to be comfortable throwing down 5 (Cheetah), taking hand out of my naturally high rev shot (Shark) and throwing my spare ball on spare shots on the left side of the lane.   I'm not sure I would have had the motivation to work on these things if I stayed on THS leagues.

MK

I thought about getting a spare ball, but 100 bucks for a 10 week league isnt worth it to me. I see the importance, but for now I have been comming straight up the back and hard at spares. If i bowled tournaments i would get one. i am mostly a league bowler during the week.

You have to look at sport leagues in terms of what you really want from the game.  Nothing at all wrong with bowling on house shots and enjoying throwing high scores.

 If you really want to become accomplished at the game, and appreciate the challenge of attacking diverse lane patterns, then sport leagues are the way to go.  When I was young and looking to get better, we didn't have sport leagues, and frankly I didn't find it productive to practice on brick yard conditions.  However I did try to bowl in multiple houses where the house shot might be off the corner in one house, and at 3rd arrow in another.  It forced me to develop a style where threw a strong enough shot to carry from inside, but could still go straight enough to play outside with minimal out angle.

 New surfaces and ball advancement forced me to refine my release, and develop more ball speed, but many of those fundamentals are still applicable.  Most of the greatest bowlers of the past 50 years who endured for any length of time went much straighter than most of the other players.  Indeed what makes Jason Belmonte so good is that he can manipulate his axis rotation to straighten his shot as much as possible with his incredibly high rev rate.       

I am envious of those that have access to a sport league.

In sport leagues you definitely know when you throw a bad shot.  You will find when you go back to a typical house shot that you will throw a bad shot, expect a bad result, but still strike.  At that point you realize how much easier a house shot is than a sport shot.

I always use to say, no matter what I was bowling on, that I try to find an angle that gives me the most margin of error, then do my best to use the least of it.   

I always use practice to try a few different angles.  Once I find one with a good look, I then start missing left and right on purpose to see if I have any margin for error.  If I do, I stick there, if not I try one of the others to see if there's more miss room.  I don't "try" to miss when it counts, but I'm realistic to know I am going to no matter how locked in I may be.  Knowing I can get away with a small miss gives me the confidence to not think and just do. 

So the problem I run into the one time a year I get to bowl on a sport shot (Nationals) is that I am too tight because my head tells me I can't miss at all.  All of a sudden I can't hit the broad side of a barn because I'm trying to be perfect.  I've done CATS in Reno.  My accuracy was professional level.  It's not that I can't be accurate, but it's difficult when you never get the chance to bowl on a tougher condition. 

I really think everyone should have access to a Sport league.  I have no idea how to make that happen, but I don't think bowling can take that next step if people don't even have the option to compete on a tougher condition.  People don't appreciate what the pros do because most of them have no understanding of the lane conditions.  To be fair, many recreational bowlers still wouldn't know after bowling in a Sport league, but some would.  And even if it's only a few, that's a good thing.  Then we need to reward people for success in the sport league - real success.  Something quality for averaging 200.  Something quality for a 300.  800.  Heck, even 700.  Give people a reason to want to aspire for the challenge.  Make them feel good about averaging 200 and reward that.  Invest in your bowlers; invest in the sport.  Other bowlers will start to get interested when they see that averaging 200 in a Sport league is more rewarding than averaging 220 in a house league.  You can't just ask people to get excited about shooting lower scores and expect it to work, but you can give them an incentive to do so.  It might work, it might not.  At the very least, it will generate some discussion that isn't taking place now.

If it's the 47' Scorpion you probably aren't going to be able to get it back from 7.

How bout throw the bowling ball down the lane, watch what it does, then adjust than trying to bowl on a piece of paper