Neck edge in cardigan pattern question

Hello, I am looking for some help on this pattern please.

I am knitting a Martin Storey boys cardigan pattern, age 5-6, and I have now reached the instructions on shaping the shoulders and back neck. See attached picture.

I have finished the first side of the neck/shoulder, which was worked with 13 stitches, and am now working the 2nd side. But I am confused as to why this next side calls for 19 stitches? Won’t that make this bigger than the other side and the cardigan uneven in the shoulders? Also, the pattern says ‘complete to match the first side, reversing shapings’. Does this mean I decrease the same amount as the first side (8 stitches over 2 rows) and so cast off with 11 stitches on my needle? Or do I work more decreases until I have 5 stitches on my needle as per first side, and then cast off?

Thank you in advance!

Actually both shoulders have equal number of sts. On the first shoulder you bind off 6 then knit in pattern till there are 13 on the right needle. That’s 6 + 13 or 19sts for the first shoulder.

Follow the same directions for shoulder 2 with the difference that you’ll be casting off on the wrong side row. Slip the center sts to a holder, patt to end, turn and bind off 6sts. Dec 1stitch at the neck edge of the next 2 rows, casting off 6sts at the armhole edge of the second row. Work a row and cast off the remaining 5sts.

Ah, thank you! That makes sense now!