I am not an expert, but here are a couple more possibilities.
1. The school provided percentiles based on your district and your district is slightly lower than the national standards: For example, if 98 percentile in your district would only be 96 percentile nationally and thus 126 on the scale.
2. The school provided percentiles based on age (and your child is on the young side) but calculated the 126 based on grade.
Of course, it is entirely possible that the school doesn't know what they are doing at all. Like others have posted, the 16 SD means that 132 rather than 130 should be the magic number for this test.
Good luck an keep pushing.
