Betty's question is: My problem is that because of the size of my biceps the cap of the sleeve is much larger than the size of the armscye and the armscye is too tight. In one of my books in order to get rid of a gaping armscye you turned the excess into a dart and rotated it to an existing dart. As my problem is the opposite can I add an extra dart in the armscye without making one of the existing darts smaller?
Answer: Unfortunately, if you add fabric somewhere, the fabric has to disappear elsewhere. Otherwise you no longer have a flat pattern to use for cutting the flat fabric. However, you can widen the bodice at the side seam to avoid taking any fabric from the dart. See the picture below: