Greetings and thanks in advance for taking a look at my question, which is as follows:
Below, I have a departure time and a stage time. I want the stage time to be an hour before the departure time.
However, when I try to change the stage time in a dynamic action so that it is an hour prior to departure, I get this...

I tried using the 'DD-MON-YYYY HH:MIPM' as the format mask for Stage time, but there is no difference.

Any suggestions? Thanks again for your help.