I agree with you.
At the time of inauguration on 20.06.2016, running time for SC-BZA Intercity Express was 5:30 hours, which was later reduced to 05:15 hours & further to 05:00 hours.
At...
more... the time of introduction, this train use to depart from SC at 05:30 hours & arrive BZA at 11:00 hours.
Subsequently, arrival at BZA was revised as 10:45 hours, and further as 10:30 hours.
Over past 4 years of time, its running time was reduced by 30 minutes, post assessing real-time scenario.
Similar reduction of running time can be done for Duronto as well, basis real-time scenario over certain period of time.