My script is not working fro price field in estimatew

Hi i have to claulate mark up and update PRICE in my estimate column field.
Looks something wrong in my script.

can you please advice me which is wrong in my script.

 function pramark(type){    if(type=='item'){        var result = (custcol_fhi_cost/(1/custcol_item_mark_up));        nlapiSetCurrentLineItemValue('price',result);          }    return true;  }