This is the most asked question. Pure and Simple patterns are written differently than some, and this causes confusion. But sleeves do not need to get longer as a person gets bigger around. The mid back to wrist length stays the same. The average for a woman is 28 inches. So as the body gets larger around, the sleeve needs to be shorter.
Of course, all of the top down patterns have sleeves that are easily made just the length you want, by trying on the sweater and knitting until they are the length you like.