Your blanket sounds lovely. I really like the k1, p1 rib and seed stitch too. Which are you doing? Or some other pattern, maybe. I like it even more since I got the Norwegian purl down. It's really fun to see how the stitches make the pattern. I recently finished a blanket in k2, p2 doing moss stitch/double seed stitch. It really did go quickly but I was using much larger needles, size 10 1/2 I think. Enjoy!
I should never overestimate my basic arithmetic skills.