I'm not quite sure that I understand how the words/characters learned are calculated. It seems to me that if you add characters when adding words, 你好 would count as 2 characters (你 and 好) and 3 words (你, 好, and 你好). If this is true, then the words learned should be much higher than the characters learned. However, my characters learned is higher than the words.
From this discussion
http://www.skritter.com/forum/topic?id=19825611&comments=9
it sounds like adding 你好 would count as only 2 characters (你 and 好) and 1 word (你好).
Can anyone clarify which is the way it works?