Oh is that what they're saying?! Gosh, this had me confused too! Way to go Carol!
Well, in my search to answer the Q, I did confirm that it's DEFINITELY not knit with two strands. I didn't think it would be, because, as Carol says, the pattern doesn't mention it, and they definitely would. But I double checked, and other patterns use this yarn on size 15 needles too, single stranded. (2 stitches to the inch, wow that'll be some fast knitting!).
Happy knitting Jade! Oh, and welcome to the forum