I am having an issue with delivery orders operations reference.

Issue is when it comes to making delivery on confirmed sales orders, I want Odoo to pick a particular Stock/Warehouse location of the 3 locations that we have configured, but Odoo persistently chooses only one of the Stock locations for delivery operations?!  It does not allow me to pick any other location. 

Although, I can change the From location of the stock to my desired stock location but the delivery order reference does not change to reflect this change in Stock location!

Here's the details.

1. We have 3 Warehouses and their respective Stock Locations. (Pic 1)

Warehouse 1 = Sundar WH Location SWH/Stock
Warehouse 2 = Queen Center Location QC/Stock
Warehouse 3 = Karachi Location KHC/Stock

2. Confirmed sales order (Pic 2)

3. When making Delivery Odoo generates SWH/Out/00074 Operation for SWH Delivery Order automatically and does not let me change this. I want to be able to make delivery from Queen Center (since the goods are currently at QC/Stock location) (Pic 3 & 4)

4. Changing the Source location triggers a message - Location to Update 'You might want to update the location's of the transfer's operations' (with only a close button to follow up) which I think is fine (Pic 5)

5. Problem is that even after changing the source location the delivery operation stays with in Sundar WH [SWH/Out/000xx] and NOT where it correctly should like in Queen Center i.e. QC/Out/000xx (Pic 6 & 7)

6. Here are our configuration settings for warehouses (Pic 8)

7. And finally the Sundar WH and Queen Center detailed settings (Pic 9 & 10)

For what seems to be a simple issue which should not occur, I am struggling with this. I will be grateful for any help. Many thanks in advance.

PS. Sorry I tried to upload images with this but files do not save on image upload, here too is another issue for another time :) I am hoping my query is simple and clear enough though.

Regards

Gulraiz