This pattern is for a twinset.
For the shell, you need additional 456 to 798 yards.

Finished measurements for cardigan: S (M, L, XL) to fit bust 37.5”(40”, 44”, 46.5”) and length 20”(20.5”, 21”, 21.5”)

Finished measurements for shell: S (M, L, XL) to fit bust 35”(37”, 40.5”, 43”) and length 16.5”(17”, 17.5”, 18”)