1. weather (but you knew this)
2. previous shooters - even though they run the lanes, most houses usually don't clean the backend; just lay a new shot from 30'- 40'. If there have been a bunch of kids earlier in the day, the oil's been pushed into the backend area with the hard house balls.
3. Some houses only clean there lanes only a couple of times a week. Multiply #2 above and add in league bowlers...not sure what it does to the lanes, but it'll be a lot different.
4. Number of bowlers per team per league? Your sub shoots with four and you have five would break the pattern down quicker.
5. Your team members may shoot your sub's line or use more sponge balls to burn up the line. Consistency with your bowlers is a factor.
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"Heres a Llama, Theres a Llama and another little Llama, Fuzzy Llama, Funny Llama, Llama Llama Duck. Llama Llama, cheesecake Llama Tablet, Brick, Potato Llama Llama Llama, Mushroom Llama, Llama Llama Duck. I was once a tree house, i lived in a cake, but i never saw the way the slayed the rake. I was only three years dead, But it told a tale, And now listen little child, to the safety Rail. Did you ever see a Llama, Kiss a Llama on the Llama? Llama Llama's, Taste of Llamas, Llama Llama Duck.
Half A Llama, twice a Llama, Not a Llama, Farmer Llama. Llama in a car, Alarm a Llama, Llama Duck Is that how its told now? Is it all so old? Is it made of Lemon juice? Doorknob, Ankle, Cold. Now my song is getting thin, I've run out of luck! Time for me to retire now, and become a duck! "
http://www.albinoblacksheep.com/flash/llama.php