If there's one thing we all know that will never be perfect, it's speech-and-handwriting recognition software. No matter how lenient Brain Age may appear to be, most of us will have to re-learn how to speak and write. The English language allows so much room for sloppy script and jumbled words - that means the quirky way you write the letter "e" is going to land you a ton of trouble here.
Same goes for speaking. While the vast majority of speech tests work fine, hearing "Blue, blue, blue ... blue?" over and over again makes it painfully obvious that a lot people say words differently - and not knowing the "correct" way to pronounce things will make you seem 50 years old when you're really 30. You've got to learn how to beat the test, which of course means your improving score isn't so much you getting better, but rather just you growing accustomed to the routine.