JoeLister considers two functions "automatic fulfillment."
The first function is sales processing: this includes decrementing quantity when a sale is made and updating the sale to the eBay sales tab of JoeLister. For FBA listings, we decrement quantity when payment is received, and the fulfillment order is put out. For MFN listings, the quantity is dropped appropriately when payment is received.
The second function of "automatic fulfillment" is order placement. By default, we will fulfill orders for your FBA items automatically through Amazon FBA. For MFN listings, order placement means we will email you to manually fulfill the order each time a sale is made.
If automatic fulfillment is disabled in the advanced settings tab, neither of these functions will be executed.
A few case studies:
If you only sell MFN - leave automatic fulfillment enabled to have your sales tab updated and receive emails to manually fulfill; disabling will mean we don't track sales at all for your items
If you sell both AFN and MFN - leave automatic fulfillment on to auto-fulfill FBA and receive emails for MFN; disabling auto-fullfillment will mean no emails/processing for MFN sales, and no automatic ordering through FBA
If you sell only AFN - leave AF on to have us place FBA orders for you; disable AF to manually put in orders through FBA etc (note that disabling will mean we won't track sales either, they wont show up in the sales tab display)