Hans did another experiment on ETS's practice academic discussion #2.
This has 120 words, and he deliberately tried to write in generalizations, with little concrete detail. E-rater gave it 4.0.
The global average TOEFL speaking score is 19. The Japan average score is 15. For our students who take 4+ months of classes, the average top TOEFL speaking score is 23. Why? Because they don't use templates! If you have a clear voice and practice regularly, you should get 23 consistently too.