The pattern is correct. You increase once at the beginning of the row and knit across. I've made many of these because they are so fast.
Here's another pattern just to compare. You can see a slight variation in the cast on number and the number of stitches before the increase. Te end result is very similar. This one is how I do them.
http://tilla2-irisknits.blogspot.com...hcloth.pattern