Just a thought, and keep in mind that I'm just a carpenter, and definitely NOT a sawyer...When I'm re-sawing thick dimensional lumber on my bandsaw, I have to be sure that my blade teeth are sticky sharp, the band is singing tight, and the guides are as close to the material I'm sawing as possible otherwise the blade will just wander and follow the grain of the board and give me a terrible wavy result. Not sure if thats applicable to your mill and your situation, or if those adjustments are even possible.
