Selling is not a science. This is what sellers who are scientists (app developers, crop consultants, engineers, IT experts) quickly and frustratingly discover.
One plus one is equal to two is scientific. When selling, the answer depends on how the question is perceived. As such it could be an is equal to sign, or the number eleven, or two ones.
How you see it, is not how the buyer sees it; and each buyer sees it differently from you, and so your job is to align your respective views. Hence why it is an art.
If only selling were a science (Sigh). This was the reaction by the team of crop scientists I was training a few weeks back.