Kevin,

I'd tend to agree with both Mike and Jim. However, there's one consideration that your post did not address: What is the likelihood that additional group by statements may be added? Right now, you're at four, which means that there will be four SPs to be maintained. If, however, that number is liable to increase, then the additional maintenance may not be worth it.

Several years ago, I was in a similar situation. There were a limited number of fields. Since that time fields have been added, and currently, if I were using SPs, there would be nearly 30 of them.