In the context of the scene, it seems to me that the question's context is different from the other answerers' interpretations: the actress who was going to play that part backed out after they bought her wardrobe, so if she were the same size, it would save them money. They think He thinks so little of her, or expectexpects to pay her so little, that this small fact is significant to him.
At least, that's what it meant to me when I saw it. Only a little of it is stated, but to me, it was all implied.