Ok, this Ravelry project shows the back pattern more clearly.
In the first picture, you can see that there's a break in the fleurette pattern at the center back.
I don't know why the directions put in the mysterious reference to "7sts at the center of the chart" when they write out the directions for the following rows, but I believe thay are referring to the rightmost section of the Size Small Horseshoe & Lace Pattern Chart (9sts in that section). They want you to do row 5, the center 7 sts which are:
k1, yo, k1, S2KP, k1, yo, k1.
The directions for the next dec row seem to follow that pattern and begin to look like the center motif in that back row.