SAP purchasing process: Invoice date before PO date

In this post, we take a look at a popular question for the purchasing process:

“Were invoices received before the actual purchase order?”

This question is described below with reference to SAP® content, but can be transferred and applied to any ERP system.

The ultimate risk of this process deviation is that the actual release process of purchasing happens in the purchase order (or requisition). Thus, orders with reviewable volume and its release can be circumvented.

First of all I want to point out that SAP is technically not able to later register the reference of an incoming invoice to an order. Entering an invoice with reference to a purchase order is not possible in an SAP system before entering the actual purchase order.

So why does this case oftentimes occur in businesses and how can documents with this process weakness be identified?

The steps of a process

The steps of a process usually run one after another, which makes it easy to order them by date. These key date fields are described below in their characteristics and handling.

When creating a purchase order, the system automatically assigns the creation date (AEDAT). This makes it possible to clearly determine the posting/entry of a purchase order. In the area of invoice receipt, processes intersect with financial accounting, which is why particular attention should be paid to the following three key date fields:

• System date (CPUDT)
  This is the date of the receipt of invoice entered to the system, is assigned by the system and cannot be changed.
• Posting date (BUDAT)
  This date determines in which period the stated amount has to be posted to. So it corresponds to the assignment of costs to a certain posting day and can be freely chosen within on open posting period by the agent.
• Document date (BLDAT)
  Provides the date on the invoice paper of the vendor. Depending on the use of automatic detection mechanisms (invoice scan) a date is proposed, which can be changed at any time by the user.

The question is now, on what date the generating of the order is to be compared.

From a technical point of view, the system date (CPUDT) makes no sense, as the invoice receipt can also be entered with an order reference only after generating the order. Thus, the difference calculation would not provide results.

The comparison with the posting date (BUDAT) is only of limited significance, as this date is used for valuation purposes in accounting. It is very likely that within a given period (e.g., a month), the exact date of invoice receipt is not recorded. Instead, the last day of the relevant period is often entered, if retrospective posting is even required at all.

In the end, only the comparison on document date (BLDAT) leads to a result. The date on the original invoice document proves the actual date of the invoice. When the document date is older than the related purchase order (AEDAT), this is the indication that the invoice was received before the purchase order was entered. However, there is a restriction with this date. It can be manually entered and editing is also possible.

In summary, the difference between the invoice document date and the creation date of the purchase order is the most reasonable to be looked at. The fact of the possibility to edit this field looses impact, when clear findings prove this approach right.