I think this is a photo
of the scarf taken from on of the projects on Ravelry. It clearly shows the decrease for the ruffle.
It may take a bit for the effect of the decreases to become obvious. I see that you've knit several rows but if you're on gauge and down to about a third of the stitches it should work out.
How wide is the ruffle before the decreases (approximately, I know this isn't easy to measure). Did you knit the gauge swatch in pattern?