It's not easy to focus on incoming code while trying to check if you've catched the last word (for me the joy of a "no error word" becomes immediately the panic of losing the next one ...). It is probably better to put your eyes only on keyboard right to the end of the exercise (now I try to do so)
I am on lesson 5 now and I notice there is no right or wrong way to do this. I try to mix and match it sometimes. I change the overall speed ,sometimes i change to tone and sometimes I also do the Morse Machine. When I am driving I listen to morse on my phone.
All in all ,learning morse really needs patience to persevere,esp after moving to the next lesson which is really frustrating.