No DS is not unhappy. He's fine with the instruction group... he says he is in the highest group so what else can they do?
I just wasn't sure if I should do something but these are all really good points. As long as it isn't hurting him!
We have a similar situation with DD8, only she doesn't like to read independently. I still think there is something more going on than her just not wanting to read and we will continue to look into that...but I digress. She is in the top reading group for her grade same as your DS, however, there could very well be a huge difference between her level compared to the level of the other students in her group. She likes her group and they seem to get along well, but I totally agree with what you have said are your concerns - if she is a more advanced reader than the others in her group are we hindering her by not speaking up. I don't know what level the others are at and I wouldn't ask, even though I could probably guess.
Last year (1st grade) the AR levels were posted on a chart in the classroom, so all one had to do was go check it out. She set a goal of getting to a 4th grade AR reading level on the chart. Soon after making that goal she got to somewhere around AR 4.2 on the chart and she stopped. I asked if she wanted to set another goal and see how far she could go and she wasn't interested, so we let it go. There was one other boy in her class that she was sort of competing with and he also made it to 4th grade AR level. Other than that, no other student on the chart was close.
When I first read this thread I agreed with several other posters that you should just let this one go (no harm, no foul). But the more I thought about it and compared it to our situation the more I wondered if we too are just letting this one slide and I started getting fired up. You say what else can they do? Once again how about school meeting the student where the student is at. If an 8 year old reads and comprehends at a higher level, then why can't they go to that higher level for reading? Now I don't mean I want my petite 8 year old 2nd grade baby going to a hormone filled 6th grade class (just a joke people, don't get upset) just because she can read at a 6th grade level, but why can't she go to 3rd or 4th grade (probably also hormone filled in this day and age) for reading? Yea, yea, yea - the school's class schedules don't match up - we have heard that plenty of times before - poppycock people, make it work!!!