What I was referring to was a waypoint which lies on the FIR boundary. Look up SITET for example.
It is exactly the same thing as specifying EGTT.
Obviously, if the waypoint lies on the FIR boundary AND happens to be on your chosen route, then it's an alternative, but 99.9% of the time, your track won't take you over a waypoint that also lies on the boundary - hence why I always use EGTT/LFFF - for channel crossings, at least..