His point is not that the 18M would have been affected, but the number of iPhones sold was down because of the waiting. e.g. if it was 15M iPhone 4Ss sold, it could have 20M, thereby beating out the S3. So iPhones sales were down the previous quarter than 'normal' but also higher this past quarter than 'normal' after the waiting was over. You'll then also get some people (including Apple) saying it would have even been higher if they could make them faster.
1/8/13 at 2:39pm