Problem with PO InfoUpdate. PB00 + RL01 becomes new PB00

Question

Hi
We are trying har to implement the correct use of conditions on Vendor / Sub-Vendor / PO and so on.
But we have one problem.
We have added condition RL01 with the value of 20% discount on Sub-Vendor "NDP"
The Info Record for Material X and Vendor X has the following info:
PB00 = 1000 USD (validity to 9999-99-99)
SUB-Vendor = NDP
So when new PO is created we get 1000 USD - 20% = 800 USD is the net price - so far so good.
The InfoUpdate indicator is ticked by default and we save the PO.
Next time we do a new PO the PB00 has changed to 800 USD and the RL01 is still -20% giving us a new net price of 640.
And this becomes and endless loop where the gross price - vendor discount becomes the new gross price on the next PO.
Any ideas?

Answer 1

Here is the Material Data on the PO, InfoUpdate is ticked:
So first PO
Then I save the PO and next time create a new PO on the same material:
As you can se the Net Price on the first PO becomes the new gross Price for the next PO. This loop goes down to 0 over time. I just want the chnage in PB00 to be transfered to the Info Record.