Transfer variance is a big topic. If you want to break down and cry, read this post and all its 37 replies:
We went on several tangents, but it might prove useful to your endeavors. (We are std. cost here; sounds like you might use average?)
But, point is, there is a place for transfer variance, even without “interdivisional accounting,” which thankfully we decided against.
Do you have GL controls on the plant transfer definition (site maintenance, I think)?
EDIT: You know, it’s something else when I am the only person in the history of this forum to ever mention “interdivisional accounting.” Twice - once here and once in the post I linked to above. And we avoided it after all. So, this is not exactly a well-beaten path, I guess!