Hi, Seattleissmart,
Without knowing more information, it's difficult to know what exactly is going on, however, I've read in more than one article that gifted kids don't always get As. Your ds's grades are still good--above average, but I understand why you're questioning things considering his MAP scores. Has he always been getting Bs? Is he bored? Is there something else going on? Is there a gifted program and is he in it?
I read here recently an article that explains the differences between high-achieving kids and gifted kids. It may be of some help.
Here it is:
http://www.giftededucation.org.nz/documents/high-achievers-pdf.pdf
