"If I have no problems then I create them myself", is that your ideal approach?
I do not see much sense in reinventing the wheel. And honestly I never saw in 18 years that someone cared about how much is loaded into runtime environment when calling a standard SAP given function module.
But the PO history has to be understood, as it collects many different documents, in an ideal world you have 1 receipt and 1 invoice for a single item, but in real world there might be hundreds of partial receipts and cancellations and re-entering and then as well as much invoices and even more for additional costs like freight, customs etc.
And to add more complexity, history can be aggregated and then a direct EKBE access would certainly be insufficient.