When I go to "Settings >View all Subscribed Threads" I get 50 pages that show every thread I've posted in all the way back to 2003.
It shows 1937 threads, many of them having more than 1 post in them.
With 4803 posts, that's an average of ~2.5 posts per thread.

It seems that you tend to have 10-12 posts in any given thread, so only showing 33 threads with a post count of 227 doesn't seem unreasonable.
Are you sure one of those 33 isn't what you're looking for?

The limit of 100 results from the advanced search is a setting on the forum that only Lester can change.

The Google link I posted may also be useful, if you refine the search by adding keywords ... it should come up with what you're looking for.