I believe that method will give you a list of the threads the poster has posted in. Not just the specific posts. You'd then have to go through all the posts in each thread to find the specific posts.
If you go to the User's profile, go to "statistics" then click on "Find all posts by [User's Name]" and you will have a list of only the posts by that user.
For example, here's the result of that search using the OP's user name:
http://forums.pelicanparts.com/search.php?searchid=5349296