Summary Problems

Hello,
Having a weird problem that I seem to be stuck on.

Trying to get available qtys, backordered and on order from multiple locations. That works fine, but when I try to get a min due date for a purchase order the quantities come in completely wrong.

Example: Item Search
Criteria =>
              Inventory Location is any of x,y,z
              Type is Inventory Item

Results =>
             Name (GROUP)
             Location Available (SUM)
             Location Back Ordered (SUM)
             Location On Order (SUM)
             Formula:numeric (SUM) =>                                                 (NVL({locationquantityavailable},0)+NVL({locationquantityonorder}, 0))-NVL({locationquantitybackordered}, 0)

At this point it works perfect, but when I add the following line all quantities completely change