Decreasing and Increasing on same row and ending with a lot more stitches

I was searching for info on what I could be doing wrong on this pattern, and ran across someone else with the same problem—and the exact same stitches—this is for the Martha Stewart Coming Home Poncho, for the scalloped edge — the pattern is Row 1 knit, Row 2 knit, Row 3 Purl, Row 4 begins k 2tog 3 times, *yo, k1 6 times, and that is repeated across the row. You begin with 90 stitches, and the pattern states ‘you will have the same amount of stitches when you end as when you began.’ Not me! I started this on different needles about a year ago, and ended up with several stitches more than 90. Last night I used different yarn and needles, and the same thing happened … Instead of 90, I had 108 stitches. I just can’t figure out what I am doing wrong. I was so careful to follow the pattern exactly and yet this happened again…am I missing a k 2 tog? Somewhere? That amount would mean I missed 2 & 1/3 of the k 2tog…lol…or something like that…
Can anyone help me? I really want to try this pattern! And succeed!

Row 1 knit
Row 2 knit
Row 3 Purl
Row 4 (k 2tog) 3 times, (yo, k1) 6 times - and that is repeated across the row.
You begin with 90 stitches, and are supposed to end with 90 sts.

Based on what you provided above, you can’t start and end with the same number of sts. The 3 k2tog will only decrease 3 stitches, while the 6 YOs will increase 6 sts. Thus, you will have a gain of three each time you do the repeat.
Either the K2tog has to be worked 6 times (to match the YOs or the YOs need to be only repeated 3 times (to match the k2tog)

Addendum: I checked the LionBrand website and row 4 above, as you have it, is incorrect. It should be…

Row 4 *[K2tog] 3 times, [yo, k 1] 6 times, [k2tog] 3 times; repeat from *.

Now you have (3 decreases, 6 increases and 3 decreases) per repeat. All is even!!

Yes, that’s a Feather and Fan stitch pattern and you begin with 3 decs, yo k1 6 times and do another set of k3 decs. Then repeat those 18 sts across the row. Don’t forget when you do the decs after the yo section that you have to do another set of decs before the next yo section, so you really have 6 decs together because of the end and beginning of the repeat.