Shipment cost transfer to invoice - condition twice in invoice

Hi experts,

I created a stat. condition in the SCD and calculated a vaule which I need in the invoice to calculate the total.

I have 2 items in the SCD - one of the header and one of the stage level. For both the condition is found and calculated with the same value.

E.g. on header level 5€ and on stage level 5€ (same condition record).

Transfer to invoice is working but I get the condiotion twice. both 5 €.

Should I calculate only on one level?

What is the reason and how can I solve it?

Thanks and regards

Marc