Oh Hi, I ran into your similar post on another forum; here's what I wrote there.
You would have to start with the right number of stitches for the repeats. Then, if you add sts like with pfb that's going to throw off the repeat.
So in the even rows 2-6 you could - *p1, yo, k2tog; rep from *. to make the ribs 3 sts wide instead of 2. On even rows 8-12 it would be - sl1, k1, psso, p1, yo; rep from *. Or you could have the purls at the end of the sequence. Then the alternate rows would be p1, k2, or k2 p1.
sue- knitting heretic