Yes, WJ-III seems to continue until it stops. DS7 (6.11 to be exact) said he solved a system of equations but stopped when asked about sin/cosin functions.
In retrospective we may not take any achievement test in the future now that we understand better about it. It's not the accuracy or interpretation of the test result. It's just we don't think a 3 hours test can provide more accurate and in-depth assessment in helping the learning plan, compared to the benchmark done by the school.
Thank you all for the good information and discussion.