"I am a Parts Manager / Purchasing Manager for a Refrigeration / HVAC / Commercial kitchen hot food equipment repair. All three divisions have different hourly service charge amounts."
You asked about PO#. If this is not Your PO, but your Client's, then you put this on the Sales Order or invoice or sales receipt.
"Example...A major pizza chain at one location could have 3-4 different job #s at any goner time at one location by 2-3 different divisions. How QB's is de up now it only shows the customer/ location/ store #. A job# in the PO on each line would. E perfect."
If you are tracking Jobs by customer's PO, then use the PO number as the Job "name." Typically:
A PO to you from a customer = your SO. PO is an available field on that transaction and on the invoice.
A PO from you is to a supplier.
"I could do a couple orders a day from a certain vendor instead of each job# getting a PO for 1 item and and a freight charge. I could bring in 10 different job #s under 1 purchase order."
If I give you three POs in the course of a week, you can enter three SO. Then, you invoice me at the end of the week and invoice for everything on all three SO, or individually. If you put them on one invoice, you SO line can show on the template on screen. That SO has the PO number noted on it in the Header.
You have Enterprise; all of this is provided for.