After receiving a few support issues on the topic, I would like to confirm both Setup and Process Flow in regards to Planning and Jobs.

1. The Job Planning Lines of 'Line Type' = "Schedule" (or "Both Schedule & Contract") (NAV2016 or prior), or "Budget" (or "Both Budget & Billable") (named starting in NAV 2017) is your demand.

2. You must have 'Usage Link' = YES on the Planning Line.
(Note - You can set 'Apply Usage Link' = YES on Job card so Planning Lines are automatically created with 'Usage Link' = YES)

PROCESSING STEPS:

1. Set Item 80005 with 'Reorder Policy' = "Order"
2. Create a New Job and set 'Apply Usage Link' = YES.
3. Create Job Task, and then a Job Planning Line of Type "Both Schedule & Contract" for Item 80005, Qty = 5, Blue Location, and notice 'Usage Link' = YES.  This is your demand for Item 80005 for this Job.
Shown below in NAV2016 version...

3. Run 'Calculate Plan' within Requisition Worksheet for Item 80005....which creates a Line for 5 qty.
4. Choose 'Carry Out Action Message' which creates a new Purchase Order.
5. Go to the Purchase Order, and notice the Purchase Order has 'Job' and 'Job Task Line' blank, but the 'Reserved Quantity' = 5

6. If we drill into the Reserved Quantity field, we see it's reserved from the Purchase Order...

It is by design the reservation is created, and the 'Job No.' and 'Job Task No.' fields on the Purchase Line are left blank.

7. The next step is posting the Purchase Order to bring quantity into stock.
8. Now from the Job Planning Line, you can click 'Create Job Journal Lines' while on the Planning Line and then Open the Job Journal.

9. Post the Job Journal

10. Now you have your Linked Job Ledger Entries of Usage for the Planning Line.