Elements Organizer Loses Date/Time when Original File Changes Location

I spent some time this week updating the date and time of many of the video clips in my Organizer catalog (by right-clicking on the thumbnail and clicking 'Adjust Date & Time').  I decided I wanted to change the file structure in my MacOS Finder, and afterwards, when linking the catalog item to the new location, I found that the Date & Time I had set had disappeared and reset to the 'Date Modified' date.

Is there a way to prevent this from happening?  I'm not married to my file structure yet, and in fact, I may move the original files to an entirely separate external hard drive.