Sometimes we have to order in multiples from suppliers. In other words, we buy boxes of 6 where the supplier has a SKU for that pack, and we then sell them individually. So we have to order a different "product" to replenish. I can mitigate this by marking the suplier SKU with a x6 at the end, so we can adjust manually.
Similarly, for other products, we order in singles and then sell them as 3-pack bundles, so we can mark the supplier SKU with /3.
But if we are automating the ordering process with a new add-on, these exceptions will cause havoc unless these adjustments are built into the system.