The date/time values whether it is day/month/year or mm/dd/yy is actually a value set in the control panel under date/time.  It is the value set for your system. You can control the value in tools --> options --> view for projects. I develop processes for factory shut downs and we usually just change the value to date and time because the tasks many times are estimated in 4, 6, 8, etc. hour time blocks.  We also use the 24 hr. calendar and use resource calendars to set the actual times.