Dear @LindieBotha,
thanks for reaching out, please refer to the answers of your questions in order below:
1- yes, this field represents the UUID in your invoice, which is A Unified Unique Identification Number (UUID) is a 128-bit number used to uniquely identify information in computer systems for E-Invoice Generation. The UUID generation scheme ensures a high probability of global uniqueness without requiring a central database check.
2- UUID that assigned to each generated invoice must be unique & shouldn’t be re-used again, so this is 100% normal to see that it’s not with the same format, and it’s an autmoatically generated value within the compliant E-invoicing solution (EGS), taxpayer’s EGS should automatically generate & store the UUID value inside the XML invoice to be compliant with ZATCA’s requirements.
3-
the invoice number: it’s the same as the invoice reference number (IRN), which is a unique, sequential note number, issued by taxpayer, as per Article 53(5)(b) of the VAT Implementing Regulation. This implies IRN is just another name for Invoice Sequence Number.
Invoice Contuer Value (ICV): as specified in E Invoicing Resolution, the Compliant E-Invoice solution must have
a tamper-resistant Electronic Invoice counter that cannot be reset or reformatted. The
counter must increment for each generated Electronic Invoice or associated note and
the Compliant Solution must record the value of this counter in each Electronic Invoice or
associated Notes. Example 1,2,3,4,5.
once the e-invoice is generated, then its ICV shoudn’t be re-used again, taxpayers should ensure that each (EGS) has its own sequence of ICV, taxpayer can upload invoices with any order, in example, the EGS is generating invoices in the sequence of (1,2,3), then the taxpayer can upload invoices to ZATCA with the order of (3,1,2) or any other order as long it’s generated as a sequence from the EGS. the validation will held at the backend not upfront.
I hope this answer your questions, if you needed any further clarifiactions, please do not hesitate to reach out.