How to block the Statistical delivery date in purchase order from updation

Question

Hello All,
    We have the following requirement from our client.
The client wants to track the delay in delivery of purchase orders raised to vendors. Currently the users, change the delivery date and then process the PO if there are any delays. The client wants to STOP this and track any changes being made.
    We created a new screen layout for purchase orders and checked the Statistics relevant delivery date as DISPLAY
However, when we tested the same, the statistical delivery date was changed along with delivery date, when the delivery date was changed in the Purchase order, though the option for statistical delivery date was seen a DISPLAY field only.
Please provide us your suggestions on any other options available.
R's
Manoj.

Answer 1

if your client wants to track the delay of a delivery from your vendor, then he has to give the vendor a chance that he can deliver on time. And the usual way to do this is by sending the PO to the vendor.
if you cange the delivery date before output of messagem then your vendor could not even know the original delivery date, so it is not the vendors fault if he cannot meet this date.
if you change the delivery date after output of message , then the statistical delivery date will stay with the old date.
the field is always open to maintain because it is not always the vendor who is reponsible for a delivery date change.
if you want to change the delivery date because you can take the quantity at that date, then it is not the vendors fault, in this case you have to change the statistical delviery date to evaluate the vendors delivery performance against the new date.
And often forgotten in this evaluation process is the warehouse personell that finally posts the goods receipt. if they post it with delay and do not change the goods reeipt date, then the vendor is as well evaluated to bad.