All three rows have now been covered and every letter is available. The next step is to use them the way they are really used: in words.
Inside a word the letters stop being separate movements and become one sequence. The hand learns the frequent sequences and starts producing them in a single sweep. That, rather than the speed of one keystroke, is what makes a fast typist.
If some letter is still shaky, go back to its row. Practising words with a shaky letter cements the shakiness, not the word.
The drill uses ordinary words. Do not chase speed yet: type evenly and let the hand learn the sequences.