Confusing pattern instructions

So I’m trying to knit this vest (size XS/S):

I’m struggling with this section (page 3):
[I]Keeping cont of pat, inc 1 st at side edge, as before, on every following 12th row from previous inc twice more, AT SAME TIME, dec 1 st for front edge (before Cable Pat) on 2nd and every following alt row once more, then every following 4th row 7 times. 37 sts[/I].

At this point I have (RS, left to right) 6 purls, a cable pattern with 19 sts, and 19 purls for 44 sts. I need to end up with 37 sts.
I got help with that already: I need to increase on the side and decrease on the front. The trouble is I need to decrease 9 times on the front, and I only have 6 purls there, so I can only decrease 5 times before destroying the cable, right?
Sorry for all this text. Can anybody help me?

Right, after you’ve decreased enough sts to eat into the cable pattern, just knit the remaining sts of the cable in knit or purl sts. You just won’t have enough to cross at the edges anymore.

You have a 3-stitch leeway for the first 10 rows of cable chart A.

Once you get to row 11, you won’t have enough stitches for the cable that starts on the edge. I’d double check the picture, but probably when you get to that point you just work those stitches in stockinette.

I’m sorry, I don’t understand. Do you mean I am supposed to eat into the cable pattern? Won’t it look awkward if the cable just cuts off into stockinette stitch? The picture doesn’t show the shoulders…

Yes, you stop doing the cables when there’s not enough sts at the edge for them. It doesn’t look as weird as you think, take a look at the picture in the pattern, or other projects people have made. They flow into the seam/edge more than you think.