Airbus a321.
Have You considered the fact that this is wrong terminology from ATC, due to the fact that one little Double transmission actually makes it sound like the format of a clearance, Ie: " NRC 840 ( Expect to) climb to FL350" the ( being the double)?
This is why I love the Dutch at Maastricht :" XYZ Request FL 350 to cruise "
MAS: " Expect so!"
Anyway, Airbus a321, when the day once come, and it will , when You make Your first mistake, lets hope it does not involve operating heavy machinery.