The plus would be that, if you intend to have him do any of the summer programs, he might be able to do some of the programs for the older kids sooner if he is officially in a higher grade. However, some of the summer programs require both completion of a certain grade and being a certain age.
Cricket, the age-based program placement is something that we're about to encounter; he's starting a PTY this weekend. He's in a math class (his least advanced subject), so I expect this will be a good fit. During the summer and fall he'll be in a 3rd/4th class (if we bump him one grade), so that might work out okay. Thanks for taking the time to reply.
Grinity, thank you for your opinion and personal story about your recommendation experience. I'll go put the form in my purse now.

I suppose we'll wait for this most recent report and then give it a go. I wish I had applied fifteen months ago when we got his first results, and before he started first grade. He was so different then. I had no clue what I was in for at the time.