I have the book.
You start with 193 sts. You have not decreased or increased at all up to chart C. (Every time you YO, you decrease, so it should still be 193 sts.) The last st is different, so it’s 192 sts divided by 24 pattern sts in C, and then means you repeat that pattern 8 times in each row. In row 7 of C, you lose 2 sts in each repeat of the pattern, so that’s 8 times, so that’s 16 fewer sts, so now 22 sts in each pattern repeat, and a total of 177. Chart D starts with 22 sts in each repeat, so that works.
Now-- if you don’t do the decreases in row 1 of C, the way she tells you, then the 2nd time you work C, you will start and end with 22 sts in each repeat, and still 177 sts. Here’s what to do to compensate:
Do you see how C is divided into 3 sections, the middle section having the YOs, and the outside sections having some purls on the right side? See how on each side of the middle section, in each row, there are some P on the RS that gradually decrease as you go up? Just on those 4 sts on each side of the mid-section, it is, on row 1, reading in towards the center, P P Ktog (or SSK) P. The first time you went through C, you had 5 sts for that mini-section, but you decrease down to 4. But on the 2nd time, you are not going to do the decrease there, because there aren’t enough sts to do so, because you only have 22 sts now each pattern repeat. So instead, just P P K P over the 4 sts. On row 2, (WS) K K P K (you are back up to 24 sts, because of the 2 YOs). On row 3, follow the chart exactly-- you have started with 24sts and will end up with 26 sts because of the YOs. Row 4–work over the 26sts. Row 5-- you have 2 decreases per section, that brings you back down to 24 sts. On row 6-- know over the 24 sts. Row 7-- you decrease again, and brings you down to 22 sts. Row 8, work over the 22 sts.
Does that make it clearer?
And by the way, someone else posted about this pattern and that she says a total of 78 rows over chart A, but it should be just once, 39 rows. Does your edition say that (it’s at the bottom of column 2 on page 84)?