It could very well be that you use both together. Is there a picture with the pattern? Or a link to where we can see it?
ETA--I found the pattern. With a gauge of 2 stitches per inch, you must use both together.
"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