Hi Abhradeep,
the "X" value means negative posting. As far as this document concern it is good and there are no double values in it (Look closer and you can see that on the picture). The problem appears in the BSET table because SAP didn't create all items but only two of them. In this example I provided all necessary data ( 4 E1FISEG segments with data for items and 4 E1FISET segments that carries tax information for items). If I send IDOC that contains only 4 E1FISEG segments than in BSET table SAP doubles items, and in this example if I send all necessary information then it creates only two of tham which is also wrong. Problem is that I don't know if I missed something and as I previously told I read the note 114814 where they tell that for tax item I need to provide all information which is carried in E1FISET segment. I would really appreciate from someone that had the same problem...
Best regards,
Aleksandar