Apparently I confused quite a few of you with my explanation of my placement of the raglan seam. Let me try something different.
The outermost rows of the raglan and upper sweater body are K, P (i.e. one row knit, next row purl). Originally I placed the seam in the outer rows, the knit rows of the body and arm edges. Because my outermost row of stitches is always uneven, this resulted in a very uneven seam as two uneven rows came together.
You can see the difference in this side-by-side photo. The first attempt is on the left. When I redid the seam, I placed it one row in (one row back, or one row behind, in the purl row. Thus, the knit rows of both pieces are hidden within the seam, resulting in a kind of "blank" raglan, or a raglan without that row (or rows) of knit stitches marching up the middle.
Hope this clears thing up.