Please note the following corrections:

Shape armholes
Cast off 5 (6, 6, 7) sts at beg of next 2 rows.
100 (110, 122, 132) sts now on needle.
Next (dec) row (RS): K1, k2tog, work to last 3 sts, ssk, k1.
Next (dec) row (WS): P1, p2tog ssp, work to last 3 sts, p2tog ssp, p1.
Repeat last 2 rows 3 (3, 4, 4) 2 (2, 3, 3) more times.
86 (96, 104, 114) 88 (98, 106, 116) sts now on needle.

Please continue knitting as follows:

Next row (WS): Purl.
Next row (RS): K1, k2tog, knit to last 3 sts, ssk, k1.
Repeat last 2 rows 2 (3, 4, 5) more times.
82 (90, 96, 104) sts now on needle.
Next row (WS): Purl.
Next row (RS): Knit.
Next row (WS): Purl.
Next row (RS): K1, k2tog, work to last 3 sts, ssk, k1.
80 (88, 94, 102) sts now on needle.
**Cont even until armhole measures: 19 (20, 21.5, 23)
cm/ 7½ (8, 8½, 9) ins, ending with RS facing for next
row.