The few kids I know with high WM scores tend to be very good students, often outperforming their overall IQ scores. In my own kids, my one with high WM didn't have it higher than her other scores, just more in line with her VCI and PRI whereas PS was low. She's found school to be a better fit for how she learns than has her sister whose WM is much lower than her VCI and PRI.
The only other kids I know with high WM were ones who had fairly average VCI and PRI and also had higher PSI than VCI and PRI. They are high achieving students who are often assumed to be gifted and who are tracked into honors classes, but lack the depth and abstract reasoning and ability to draw inferences that I see in kids with similarly high VCI/PRI.
I don't know if any of this would apply to your dc at all! I'm just giving my anecdotes of what we've seen in kids with WM scores that do or do not line up with their other indices.
