Good going Margie and GG!
You know, as I understand it, the designer might have saved a lot to to-ing and fro-ing if she had asked you to provisionally cast on 2 separate sets of 34sts each at the beginning of the RS row. You knit the first 3sts, turn to the WS, work the 3sts and continue with the body of the sweater. It's giving you a 3 stitch transition from the body to the sleeve at the underarm.
The reason for the provisional cast on is probably clearer at the directions for Finishing. Maybe grafting the two sides of the sleeve together.