I also have the DD7 and really like it. The time should work in 800ms mode. I believe it is only deactivated in the hold mode. Here is a link to the owners manual
it sets the range for the d time knob. if you want a quick slap back youd set it for 50. trying to get a 30ms delay when the range is 3.2 seconds would be difficult. the time on the range knob sets the max time available for that setting