Sorry Simone. This post seems to have slipped by. I've never seen a yoke with fewer rows over the sleeves. Especially without specific directions for the short row shaping. Usually the decreases in the yoke take care of the shaping and the extra fabric in the sleeves becomes part of the shoulders so you don't need to have fewer rows. Sometmes there are extra rows at the back of the neck to raise that area but that occurs toward the end of the yoke.
If you decide to do the short rows across front and back, I think your idea of spacing them out is better than stacking them up in the same place. You'll only need 4 more rows so the short rows may be a good compromise with the pattern wording.
I've checked the errata link in Ravelry and don't see any that apply to this part of the pattern.