PO net price gray out

Hi  All,

we have query , we have maintain the Maintain the conditions in the Info record .

while maintaining the info record in PO , system  is  gray out in Net Price of PO

so we have cross in the Calculation schema as well every thing is perfect but still system is gray out

we have done lot of research in GOOGLE as well but we didn't  find the correct answer

also we have check the authorization also in SU53

please advice