That is the nature of crocheting in the round. The stitches slant to the right. Take a close look at any piece crocheted in the round and you will see that the stitches are not directly above the ones below. Actually, this happens in flat crochet too, but since you turn it over and go back the other way at the end of the row, it cancels itself out.
You have to work with it, not against it.
You can draw out some right-slanting graph paper and chart your designs on that to get a truer idea of how your design will come out.
I was wondering about how to fix that in my crocheting in rounds...is it possible to get images to even up when crocheting rounds in spiral? I didn't have too many problems when I did the ss, ch 1 @ the beginning of a round when not doing spiral.