Different blending when batching?

For some reason, my function with the batching using DrawIndexedPrimitive gives off wrong blending colours, making the rendered object too dark. However, the same object with the same alpha colour values drawn individually with a function such as DrawPrimitiveUP or even in a vertex buffer using DrawPrimitive gives off the correct values. Ive checked my code over and over again, debugged like anything, so im pretty sure that the right colour values are being set. Anyone know why this may be happening?