My son's WM is his highest score, but only a touch higher than VCI. His VCI, WMI and PRI are all tightly clustered together, with PSI almost 40 points lower. It's not a pretty profile!
We also see that he uses his WMI to compensate for low PSI. He rushes through information he thinks he already knows and doesn't always read carefully. He's the kid that will get tricked easily if he's done 10 math problems a certain way and problem 11 switches the question subtly.
We're investigating 2E issues right now because his auditory processing speed seems to be completely on par with the rest of his abilities (listening to directions, telling stories, understanding stories, quick witted fast responses) but his fine motor skills are complete junk- which inhibits the PSI score on the WISC.