Before you have to export, set ruler orgin to spread orgin............
var myDocument = app.documents.item(0);
//<fragment>
with(myDocument.viewPreferences){
//Measurement unit choices are:
//* MeasurementUnits.picas
//* MeasurementUnits.points
//* MeasurementUnits.inches
//* MeasurementUnits.inchesDecimal
//* MeasurementUnits.millimeters
//* MeasurementUnits.centimeters
//* MeasurementUnits.ciceros
//* MeasurementUnits.agates
//* MeasurementUnits.custom
//Set horizontal and vertical measurement units to points.
horizontalMeasurementUnits = MeasurementUnits.points;
verticalMeasurementUnits = MeasurementUnits.points;
//set ruler origin to page origin
rulerorigin = ruler origin.spread origin;
}