Hi and welcome!
There's no way to keep the ribbing perfect if you're increasing a stitch at a time, right? Along the seam line you'll have parts where there is only one knit or one purl, depending on where you're at in the pattern. Don't worry about it. As you work the increases, they'll look like the ribs are emerging from the seam line.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry