How to Keep Current Listing ID on eBay
The products are automatically relisted on eBay, and the relisted products' listings IDs are updated. Your Primelister Inventory changes when the ID changes. It is possible to relist the same product on eBay with the same ID.
Use Sell Similar when relisting the item. The listing Duration should be changed to GTC (Good til Cancelled). As a result, until you finish the listing, it will keep the same item id number.
In this way, items will have a new item id. There is no way to reuse the previous item id number, so you'll have to update the numbers/links in the other listings to match the new one, but the number will not change once it's set to GTC.