Correct!!! We can all talk about B.O.P.'s, wind direction, how good West/East birds are, what line they take not to mention the little bit of luck they need as well. As you say it's a physical impossibility for everything to be even.
Best thing to do is enjoy the racing, do the best you can for them, set them up to the best of your ability, pay yer money n get them in there n start prayin, hopefuly ye'll get yer reward if no there's always next time