I almost never export design points, so I agree with Matt that survey coordinate timestamp for surveyed design points would best for exports. If I have imported design points, the design coordinate timestamps don't mean much. Design coordinate timestamps of manually entered or COGO points are a little more meaningful.
I like having a chronological record of what I did and when, so the time that I surveyed a point is the most meaningful. More meaningful than when I shifted, DPOSed, ReDPOSed, or otherwise adjusted coordinate values.
I wouldn't mind if the exported file had multiple entries for the same point, one for each different timestamp. Office software will alert me if I try to import a point that already exists in the coordinate file.
Thanks for working on this.