I hope I am recalling this correctly...I believe I am, as it applies to my son, and it also applies to our tester's son.
Our tester for the SB5 called several weeks after she gave us the final report and stated that she had looked in to why the knowledge scores were low, comparitively, for some children who otherwise had consistently high scores. She stated that she read that children, particularly boys, who score very high (150ish and above) in the major subtests were scoring lower in knowledge. Just an interesting tidbit at the time.
Both of our sons scored approximately the same overall, and both had much lower scores in the knowledge subtest.
Not sure if this is one of the issues you are referring to, but thought I'd throw it out there.