Wrong calculation for ZSJ3 condition type in pricing !

Hi guys,

While I am creating a billig document (VF01) I have realized that on the item level, only item 20 displays a wrong value for discount item condition type (ZSJ3). The discount has a value 10% but it calculates less than this. However if the item 20 is selected for the FIRST time under condition the correct amount for discount appears (only by the first time) by switching forth and back between the header and item level, the item 20 displays then always the wrong valued.