No Output if the Invoice value is Zero

I do not want an output to be triggered if the invoice value is zero. I have created a VOFM Output requirement routine changing the sy-subrc to 4 if the invoice value is zero (CHECK : KOMKBV3-NETWR GT '0.00') . I have also assigned this routine to the output type (RD00) in the output determination.

When I create a invoice with zero value the output is still getting triggered. Can you please let me know if I am missing something here.

PS: During debugging we found that routine is successfully triggered and sy-subrc is changed to 4 when the value is Zero.