I did it with DS10 last year (4th grade) he did very well (high honors on both parts) I wasn't thinking of doing it with DD8 because of her 2E'ness. She can't perform fast enough on a timed math test, just won't happen. First 2 skills tests they did in math she got her extra time (that's on her 504) and got 99% and 98%. On the 3rd test she wasn't given the extra time, didn't complete the test and got a 58%. Every question she completed was correct (none were skipped). So, I don't think a timed test would work out. There is no real reason to do it in our case anyway, it was fun for DS because he loves tests and does well. Maybe I'll think about it next year for DD when she is in 4th grade.