> The wording in the quote explicitly states that an FBA unit can be substituted by owned by Amazon unit or other FBA units. But the wording is not clear whether SBA (Sold By Amazon) unit can be substituted by an FBA inventory.
It would have to go both ways. If there are 10 FBA and 10 SBA units in the inventory, and Amazon decides to fill an FBA order with an SBA unit for operational reasons, now there are 10 FBA and 9 SBA units in inventory but the FBA seller only owns 9 units. That 10th FBA unit eventually has to go somewhere. The only options are that it fulfills an SBA order or Amazon forces the FBA seller to buy the SBA unit that Amazon shipped for the FBA order. As far as I know the latter does not happen.
It would have to go both ways. If there are 10 FBA and 10 SBA units in the inventory, and Amazon decides to fill an FBA order with an SBA unit for operational reasons, now there are 10 FBA and 9 SBA units in inventory but the FBA seller only owns 9 units. That 10th FBA unit eventually has to go somewhere. The only options are that it fulfills an SBA order or Amazon forces the FBA seller to buy the SBA unit that Amazon shipped for the FBA order. As far as I know the latter does not happen.