Client Script for Web Client - Not Updating

I was able to create a client script that updates the non_part_usage.user_def4 with the person’s phy_svc_grp_c based on the person’s place. If there is no person attached to the task, it will clear the user_def4. If there is a person attached, it will update user_def4 with the person’s place phy_svc_grp_c. The issue that I am running into is when I change the person’s place phy_svc_grp_c on the  place screen, it does not update to the new phy_svc_grp_c but blanks it out. 

Custom Code Assignment - On person_id on screen.

Screen Events - 

Client Script

var personID = getControlValue('task','person_id');

if (isNullOrEmptyString(personID)==true)
{		
	alert('I am true');
	var rows = getDataTableRows('non_part_usage');
	if(size(rows) > 0)
	{
    	for(var i=0;i<size(rows);++i)
    	{
        	var row = rows[i];
        	setRowControlValue(row, 'non_part_usage', 'user_def4','');			
    	}
    	saveChanges();
		refreshScreen();
	}	
}
else if (isNullOrEmptyString(placeId) == false)
{
	alert('I am false');
	var psgc = getDBValues('SP_PHY_SVC_GRP_C',personID);	
	var rows = getDataTableRows('non_part_usage');	
	if(size(rows) > 0)
	{		
    	for(var i=0;i<size(rows);++i)
    	{    		
        	var row = rows[i];
        	setRowControlValue(row, 'non_part_usage', 'user_def4',psgc);        	
        }
    	saveChanges();
		refreshScreen();
	}

}
refreshScreen();