Query about back&edit listing URL usage

Hi support team,

when a user has chosen to do a paid listing, but not finalize the purchase and would like to edit his details again he will be able to do this by using the “&backandedit=1” with coresponding listing and price id listing url. i.e. https://www.worldcheckin.com/add-listing/?pid=6201&backandedit=1&listing_type=gd_event&package_id=158

But after a while or when cookies are deleted and trying to use again this link then not all fields are displayed. Screen shot > http://awesomescreenshot.com/0886a7tu22

How long is the “backandedit=1” link available to be used?
I would rather like to use this link instead of pure edit link url because within the “backandedit=1” link, because there is the option of price selection within & all filled fields to may change available.

Reason:
A User decide to add a paid listing but then will not proceed further with purchase. Then after he decide to proceed further by using the core edit listing URL then the price select fields are not displayed. When he instead used “upgrade” then those fields are available, but for other user who have chosen the greatest paid listing price setting and want to proceed further, then the “upgrade” link is not available and they will only have the “edit” link URL available without the changing price selection any more. This would be necessary if the user want to proceed further by changing his price setting for may upgrade or downgrade the listing before he even made a payment for his only preview mode listing.

Please advice which link url will be available to use for changing price setting after he was in preview mode to be able to go back later (not only immediate) but, i.e. after a day or after may cookies are deleted.

BR, Alex