DAX Logic for Counting Quantity

Hi,

I have a specific requirement with some locations and items in my report and I need to get the dax correct, which I'm struggling with.

Its quite confusing but essentially :

• If Location 3 Quantity is greater than 0, then Location 3 Quantity minus Location 1 Quantity, and make Location 2 for that item 0
• If Location 3 doesn't exist for the item or 0 Quantity then take the Quantity from Location 2 as normal

I've included a dummy report with some more information on. If any more info is needed please let me know.

Dummy Data Location.pbix

Any help would be greatly appreciated

Thanks