What you describe with your DS sounds like dysgraphia but his test scores seems to say something else. His Coding and Symbol Search are pretty high for a kid with dysgraphia. Generally dysgraphia will affect those scores. Perhaps this is why your tester is hesitant about saying dysgraphia?

My DS has dysgraphia and ADHD. He has a large discrepancy (41 points) between his PSI and PRI. His PSI is 100. His tester also gave him the Beery Visual Motor Integration test and he scored in the 37% for his age. I think between that, the low PSI (Coding and Symbol Search) and his symptoms we arrived at dysgraphia. His WMI is above average (113).

My DD has the huge discrepancy between her VCI and PSI but she has no learning issues. Her WIAT scores and her WISC scores lined up nicely. Apparently lower PSI is common in gifted kids and does not necessarily affect academic success but the low WMI can, per the article above.

Here is an article that suggests various possible causes for written output problems:

http://www.123helpme.com/view.asp?id=121667

Also Mel Levine's book "The Myth of Laziness" discusses various conditions that can lead to written output problems. Some are neurological. I would say that between your DS' lower WMI and atypically high PSI (for dysgraphia) the neurologist consult recommendation is spot on.

Good luck!