Finally figured out what to do after the first 42 rows of chart 1!

I like to understand things completely. With Icarus being my first Lace project other than a scarf, I was in need of lace pattern directions broken down into quarks and atoms before pressing forward.

Directions say: Repeat rows 19-42 of chart 1 five more times for 342 sts. See Notes for how to adjust size at this point.
Notes say: For larger or smaller shawl, work rows 19-42 of chart 1 more or fewer times before finishing chart 1 by working rows 19-34.

Whut? Uber confusing.
Ok, I get that this sentence is to describe that increasing accordingly will make the shawl longer and wider, but how exactly to increase? According to these directions... had me a boggled.

Having already invested 42 rows (with some additional tortureous rows of ripping back and reknitting to deal with dropped sts), it was time to sit down with pencil and paper and take a closer look at the pattern.

Addition of another section for clarity would have helped me here. Something like, "for each of these five repeats, DOUBLE the two 12 sts pattern repeats at the odd numbered rows" so that:

At the end of the first section of rows 18-42 repeat, adding in two repeats of the pattern box you should then have:
2 pattern box repeats = 24 sts on each side of the center, 48 sts added, 151 sts
4 pattern box repeats = 48 sts on each side of the center, 96 sts added, 199 sts
6 pattern box repeats = 72 sts on each side of the center, 144 sts added, 247 sts
8 pattern box repeats = 96 sts on each side of the center, 192 sts added, 295 sts
10 pattern box repeats = 120 sts on each side of the center, 240 sts added, 343 sts

Having the pattern broken down this way allowed me to see how exactly I didn't need to follow along and end up with 343, how I could still go on to futz with the numbers of pattern box repeats in my way, and still keep the shawl shaping.

I hope this helps out someone else out stuck in the same spot.