yes, absolutely. Just use a calculation like this:
import System static def GetAttributeValue(Process): Timespan = EndDate - Startdate Value = Timespan.TotalMinutes
The calculation explained:
If you subtract two DateTime values, you'll get a Timespan value. The method .TotalMinutes will deliver the minutes and seconds of that timespan as Decimal number (e.g. 5 minutes and 30 seconds = 5,5). You can also use ".TotalSeconds" and other methods.
And you can do any other calculations on that decimal number like round up or down if you like or convert them to a string for displaying on a window, etc.
I hope that was what you wanted to do!