Hi Gus, I haven’t done this course and so I haven’t seen but I am am sure that the settings will be 12;17,9 and not 17;12;9 as you say.
Default values for MACD are 12 ; 26 and 9 and its best to not stray too far from the default in this case. And so in this case the 26 has been reduced slightly but that is all. Also yes the fast EMA should be smaller than the slow. Its just a typo.