Hi all, just discovered this forum a few days ago. May I ask a question on how to interpret low digit span score from my son's WISC IV test?

My son is 9 yr old. He did WISC IV test this past weekend and got the following score:
VCI: 146
Similarities: 18
Vocabulary: 18
Comprehension:17
PRI: 143
Block Design: 17
Picture Concepts: 17
Matrix Reasoning: 17
WMI: 129
Arithmetic: 17
Digit Span: 9
Letter-Number Seq: 13
PSI: 128
Coding: 15
Symbol Search: 15

FSIQ: 148

It seems Digit Span score is real low. How to interpret this? What is the symptom/consequence of this? Anything needs
to be concerned? The testing school psychologist said nothing
to be worried. But still I am wondering if the experienced parents may have seen this kind of "pattern"? Thanks very much.