Basic inventory management question

Basic inventory management question:

We use NetSuite's inventory calculations for quantities to keep in stock ...like "safety stock level = 30 days". NetSuite calculates inventory levels based on average sales per day and gives us quantities to order and such.

OK, now we've got a NEW scenario. Now we're getting orders with NO sales order and NO fulfillment, BUT these are items that we need to track inventory on. These orders are fulfilled by Amazon and we set up Amazon as a new location in NetSuite.

Each time we get a "fulfilled by Amazon" order, there is a matching cash sale created in NetSuite AND our NetSuite inventory for the Amazon location is automatically adjusted by the number ordered. There is no fulfillment and no sales order. The thing we noticed is that so far NetSuite hasn't told us to replenish the new Amazon location. We sold 95% of our inventory at the Amazon location and it never said to order more for the Amazon location. We had spotted it, so we just sent more on our own intuition.