Hi @andynewey,

to get a better understand of the entitlement upload, please check the following SAM blog post - ServiceNow SAM Entitlement Import User Guide - ServiceNow Community

#1) This is correct, the template contains the most relevant fields, but all missing fields can be added as custom

#2) You can raise all missing features/requirements in the ServiceNow - Idea Portal

#3) User/Device allocation is not possible with the template, you've to create your own data load to link the data.
It's possible to add users to each of the available user reference fields

#4) PO number is defined as the following by the entitlement upload (see box). And I was able to upload PO and Invoice number with the correct mapping on the entitlement form. Please add the field and try it again.

PO Number (optional)
This is a field specifically for your reference, should you need it. In many cases, it is helpful to have a reference back to the PO in case of audit defense, so that it is possible to prove what was ordered, linked to a paid invoice to prove entitlement, and to show delivery.
Note: In the SAM User Interface, on the Software Entitlement form, the field PO Number does not appear out of the box, even though the column is in fact part of the table. In order to add it, an admin must add it

Best, Dennis