It would be good if the "add word frequency" could be changed via the practice settings.
As I write I realise that also more generally it is not quite intuitive which settings to change via the account settings and via the practice settings.
My other point was regarding messages in the practice window. After a certain time of skrittering the messages "Type the pinyin" and "Press enter for next" are not really needed anymore. In addition, the "Press enter for next" message sometimes obscures more important text in the window, for example when the pinyin has been incorrectly written, and the correct answer is given below.
Just minor suggestions, as I said.