You are correct! I should have referred to the guide (New Forum Guide - Syntax and Features) to refresh myself. 
I recall now that I was confused by my āPosts Readā count a few months ago, and still am. I am certain I had read more than 20,000 some time ago, and definitely have by now; it is my belief that the counter is somehow bugged or may not properly increment with a slow Internet connection like my own.
Evidently, Trust Level is a rather imperfect system: after all, you should have achieved TL3 a long time ago! Hopefully you will get there sooner rather than later. 