I'm not familiar with the AIMSweb, but have a few thoughts re timed tests etc (I have a ds with low processing speed due to DCD and dysgraphia). 504 accommodations change as needs change; an accommodation of "no timed tests" probably works well for lower grade students, but as your ds moves up in elementary school he's probably going to face more situations where teachers want some reference of time - so jmo, but I'd suggest considering building in an extended time accommodation, so that he can be timed, but the time limit is reasonable based on his abilities. 50% additional time is really common, but some students need 100% or more time - I have no idea what your ds' needs are, but if you could ask this question of the person who evaluated him (when you learned of his slow processing speed), they can probably share some insight re your ds' needs for extended time.
Even if you think you don't need the extended time accommodation now, it might be useful to start advocating for it in case it's met with resistance. Eventually (at some point) your ds will need to take standardized testing (either state testing or later on SAT etc) which don't offer a "no time limit" option - so getting the accommodation built into his 504 now can be really helpful in having it in place later on.
We also had a lot of push-back from school re accelerating our ds in math in 2nd/3rd/4th and even 5th grade - the school couldn't see past our ds' inability to finish timed math facts tests, even though our he would get every problem correct and was clearly just running out of time. Our ultimate answer isn't one I'd suggest for everyone (we moved schools - but it was for more than just math acceleration). However, there were things I found helpful in advocating:
1) having testing (which you already have) showing the impact of time - you have a test where your ds clearly knew what he was doing, answered the problems correctly, but just didn't finish in the amount of time typically given for the test.
2) requesting oral response for math facts - this might not get around the timing problem entirely, depending on what the issue is behind slow processing, but it may show clearly that your ds can answer math facts quicker than he can demonstrate with pencil and paper. Note: this isn't an accommodation that you can use forward forever - it takes the time of a teacher or an aide at school, but having an example of this for proof of the impact of handwriting speed can be illustrative of the need for an accommodation.
3) the difference in processing speed on an ability/IQ test. To be honest, this didn't help us tremendously in advocating because teachers really weren't familiar with it and when you show high ability scores our ds' teachers tended to then equate inability to do something with laziness or not trying rather than a real challenge... but it was an important data point and having as many data points from different sources as possible is helpful when advocating.
4) if you have a diagnosis that explains why processing speed or written output etc is an issue, cite the diagnosis and explain it in the context of how it impacts academics.
Hope some of that helps!
polarbear
