I partly got those results because I'm bad at English...
Let me explain:
When I read: be careful with your typing, I immediately decided to write short and easy sentences.

I guess their statistical algorithm only works well with easy vocabulary, short sentences.
Example:
"I see a cystal clear bottle, with a blue label, a white cap on a white surface." Might be too difficult to score for the algorithm
but
"I see a crystal clear bottle.
The bottle has a blue label.
The bottle has a white cap.
The bottle is on a white surface."
Is probably a lot easier to decipher and then score points.