Okay! One has to use the Step-by-Step, and then (and only then) does the question pop up: Do you wish to use the pre-TCJA rules?, or some such language. I click yes, and the next question is the parents' taxable income, and we are off to the races. Thank you, Inuit!
I hope TurboTax will make it as easy to file a 1040X for 2018....
