Warning --An old scam "tidied up"

A scam from a couple of years back is starting to do the rounds again.
Sending out e mail bills.
They are targeting the accounts payable/ bill payer of listed companies.
Where they have gotten a bit cleverer than previous versions is that the bills come through as an e mail is what looks to be and is identical in format to a legitimate xero invoice from a supplier.
By using industry appropriate supplier names on the invoices it can look totally like a legit bill. Also they seem to aim for end of month. The giveaway as always is the e mail address.
Everyone in the industry here is no doubt too clever to fall for it but heck still a heads up

We use SAP at work, no purchase order number = no payment. Same if the PO number doesn't line up in the system to anything we have generated.

I get power company bills every few months which look genuine except they are not from my power suppy company. They have the name and address right but every thing else is fake

We have SAP and it still takes a whole team of invoice matching people to keep it ticking along. Eg a vendor might get a P/O number right but try to charge the wrong company code - we have hundreds :(