Can someone please help me with this part in this pattern ?

(In the red part ) So would the 9th row be
K21, increase , k7 (as the previously added 2 aka stitches from increase )
Then knit 19

Then 3 rows st st

The next increase after would be k21, increase , knit 9, knit 19 ?

Then 3 rows st st

Etc ?

Am I mistaken ?
If I am wrong , can someone please shine some light on this ?

Will be very grateful x
Many thanks

You’re on the right track.
Row 9 would be k21, inc in the next stitch, k5, inc in the next stitch, k19.
Row 13 would be k21, inc in the next stitch, k7, inc in the next stitch, k19