No, dropship360 does not require the inventory value of an item.
dropship360 will update individual Qtys as an aggregate count based on the Qtys set-up for each Supplier.
To turn this off navigate to System > Configuration > Catalog > Inventory > Product Stock Options
Set the Manage Stock setting to "No".
Note: if the Manage Stock option is set to "Yes" the product will aggregate the total Qtys of all suppliers as the total inventory of that product.
Please Note: the Manage Stock option is a Global Value and will effect this product in all of your store or websites.
When you install dropship360 you will see two new tabs on the Product Information pages - dropship360 Supplier and dropship360 Supplier History. The Supplier page is where you will add Supplier Sku, Cost, and Inventory.
Regardless of whether you are using the Manage Stock feature you can still manage and track inventory at the Supplier level. The aggregate amount will only be calculated for multiple suppliers if Manage Stock is set to "Yes".
In the above images images you will see that MagVendID1 has Inventory 9 and MagVendID2 has Inventory 25. The Manage Products listing page shows the total Inventory of Qty 34 (9+25=34).