That was average, it gaps in general were on the smaller side, as they tend to be in pan flat TTs with no wind.When Dumoulin won the Giro Quintana actually had a really good TT, losing only 1:25 on Dumoulin over 30k. And that TT was as flat as a pancake.
Results of Giro d'Italia 2017. Won by Jos van Emden before Tom Dumoulin (2nd) and Manuel Quinziato (3rd).www.procyclingstats.com
So he can produce good TTs, just not today.