+ $item->fxsellprice($item->sellprice) if $data->{is_invoice};
+
+ my $num_dec = _num_decimal_places($item->sellprice) || 2;
+ # ^ we need at least 2 decimal places ^
+ # my test case 43.00 € with 0 decimal places and 0.5 discount ->
+ # : sellprice before:43.00000
+ # : num dec before:0
+ # : discount / sellprice ratio: 22 / 21
+ # : discount = 43 * 0.5 _round(21.5, 0) = 22
+ # TODO write a test case