No they don't necessarily line up at all, I guess to some extent poor WM can slow down PS (or high WM increase PS) but issues revealed by slow processing speed are often visual, physically with the hand or hand/eye coordination issues, dysgraphia, etc. Or it can be suppressed by anxiety, or slow methodical working, or in my DDs case by doing precisely two of each type perfectly and then putting her pencil down and watching te clock for the second half if the test... We now know she has a handwriting disability so maybe the test hurt her and that's why she stopped when she felt she'd demonstrated mastery, maybe she was just bored, we'll never know... Her WM is well into the gifted range. WM is an entirely verbal test requiring no visual or physical skills though.
My other DD on the other hand has PS around the 90 th percentile but has a poor (and variable) WM and we see the differences between the two girls everyday....
