As far as the lower scores on the timed WJ III tests, that is a product of your DS' dysgraphia. More time for tests and written assignments is one of the main recommendations from my DS' tester to address his dysgraphia. This and being allowed to keyboard or having a scribe are extremely important for leveling the playing field for kids with dysgraphia.
Your DS' teacher sounds pretty awful. Poor guy! Maybe you could suggest she write on the board and demonstrate all the math problems all day one day with her non-dominant hand so she could get a feel for how every day is for your DS! Seriously, she obviously does not understand dysgraphia. Another meeting may be in order, although it is so close to the end of the year that it probably doesn't matter at this point.
You might want to meet with your principal, educate him/her about your DS and work on getting him with the right, pre-educated teacher for next year. If your prinicpal is not receptive you may be at the wrong school for your DS. The wrtitten work only gets longer and harder from 4th grade. Without proper accommodations the school will be asking the impossible from your DS and he will tune out even more. I suspect he is VERY frustrated with school right now.
It sounds like you did not get written recommendations from your testing. Is that right? You need a diagnosis and recommendations in writing. This will help right now to have recommendations tailored to your son but also will help in the future. My tester told me we needed to have new testing done every three years and especially right before the SAT/ACT. Needless to say, I have not been thinking about the SAT with a son in 5th grade but apparently some kids get suddenly "diagnosed" around that time to get extra test time. Having an early, documented diagnosis and follow up will help your DS get extra time if and when he needs it for these tests, as well as the extra time he needs now.
We are also at a private school. It's both easier (power of the purse strings, competition) and harder (no IEP or 504 rights there). Good luck! My heart goes out to your DS,
