Lightroom :: How To Keep User Order When Exporting Collection

I made a collection of about 300 VC's, chosen from many folders in my catalogue. These images were taken over a 10 year period, using 3 different cameras and having different names and file types. The collection was sorted by "User Order". I spent a good deal of time organizing the collection so that the images made visual sense when shown as a slide show on a digital album.
 
I exported the collection to my hard drive as jpegs, and checked the box to place them back in my catalogue, in a designated subfolder within my parent folder. All went well except they are now completely out of order, and that order makes no logical sense whatsoever - not by date, metadata, filename, attributes, nothing that I can figure out. I have to start all over again to reorder them - something that will take several hours.
 
How can I keep my designated user order when I export a collection? I am using LR 4.3.