Jimmy Smith had the same problem with a set of 13X31's. Big difference in the roll out, he tried everthing to get the size equal, blowing them up to 30lbs., etc. He had put soap in them to seal them. He purchased them from Bill Taylor (BTE), Bill stood behind them even with the soap in them and gave him a new set. He's very happy with the way they work, but i'm sure he would not be happy if he had your story of the cost in shipping them. I think BTE even brought a set to the track for him.
Zip.