How do I restore all images in a collection to original imported aspect ratio?

Question

Typically I select all images in a catalog, resize the first image to 640x480.  I then right click on the first image (all images are still selected) click on Develop Settings, Sync and choose to sync only the aspect ratio.  All images are then cropped to 640x480 like the first image, which I then export to a folder.
I then need to restore all images to the original aspect ratio for building a slideshow to export to my website.  I've followed the same procedure i.e. selected all images, click on the first image, change aspect to original, right click on first image and sync aspect ratio for all images.
The problem is that the rest of the images do not return to their original aspect ratio but revert to 4x6 aspect ratio instead of the original size when imported.  I've changed the lock to unlocked and tried both but still no result.  Now I have to select each image individually, open the crop dialog and choose custom to get it back to the imported aspect ratio.
How do I batch restore all images in a collection to the aspect ratio when imported?

Answer 1

Rotating an image is adjusting its crop rotation and crop size.  You originally said you wanted things back to import state which presumably was full resolution w/o any adjustments to ratio, size, or rotation.  If you are wanting to do things in the middle of your other processing I'm less sure what to tell you.
Taking a crop that you have at 3:2 and setting it to 4:3 shrinks in the longer sides, and resetting the ratio to 3:2 shrinks down the shorter top and bottom--this is how it always works, because a crop box is not ever expanded by setting the ratio to something different, and changing the ratio back and forth like that makes the crop-box smaller and smaller. 
Are you having an issue because you want to fiddle with the crop in the middle of other processing every time, or is this a special case because you've moved on in your processing after asking your question some time ago? 
If you routinely need to do this, an easier way might be to export the images at the 3:2 crop, then reimport those JPGs, change the crop on those JPGs, only, then re-export them a second time, and be done with them.  This sounds like you're making proofs?
If you are making proof-sized images at a different ratio?  Why not just export the 3:2 images at a smallish size, perhaps with a watermark and not have to worry about making them 4:3 ratio?
Another alternative would be to print the images to JPGs instead of a printer, and set the paper size to a 4:3 ratio and turn on the Fill option--which will chop of the long sides automatically as it prints them.