Anthony, when they first introduced the write it feature the application did do the rating. But the problem was, it sometimes gave false ratings. For example, if you used a period instead of exclamation mark, or a comma instead of ellipses, yet write the words of the sentence perfectly, it would sometimes mark you down. Conversely, I have on occasion made a mistake in a write it lesson that I felt I should have been marked down for, but got an "Its easy"' grade from the system. It still gives a rating but can be overridden. Also, there are some mistakes in the written testing material that the user needs to be able to compensate for when found.
Frankly, as I my Spanish has improved, I find that I have gotten tougher on myself in my grading. Unless it is a simple spelling error, I don't give myself an "Its Easy" unless I have translated the sentence perfectly.