This is a great question. It is a bit odd that a CFO would want a credit rating of AA instead of AAA. I would say that this is not a typical strategy, but there could be a few reasons why this is the desired approach.
First, in this economic climate there is not a huge difference between AAA and AA. For example, the United States has been downgraded to an AA ratings. So, an AA rating is still very much a solid rating, which shows credit worthiness. Moreover, not many companies are now AAA.
Second, this AA rating may give the impression that a company is daring and willing to take risks. This may communicate to some that this company is both financially responsible and also willing to go where others will not. In other words, they have vision and have a heart to blaze a new trail.