I've noticed when I study a new list of 25-35 characters using the "cram list" mode, that whenever I get a character right on the first try, whether it be tones or writing practice, the characters I get right on the first try don't come up again when I study that list in "cram list" mode. No matter how long I study that list in "cram list" mode, those characters never come up anymore.
One reason why I don't like this is because a lot of times I'll get a character right by chance on the first try, because right before studying the list, I made the list of words and it's still fresh in my mind. I just think that it seems when we get characters right on the first try, the algorithm thing throws them way way way in the back