Issue with Catalog Item using MRVS

[Chris33]

All - 

I am trying to troubleshoot an issue with a MRVS in a catalog Item.  The MRVS contains purchase items ...

Name   Type   Question  Order

mrvs_cost_center Reference Cost Center 100

account_number Reference Account Number 110

quantity Single Line Text Quantity 120

unit_price Single Line Text Unit Price 130

vendor Reference Supplier/Vendor 140

description Multi Line Text Description 150

total Single Line Text Total 160

When a new row is added i need to do a calculation of unit_price * quantity and then store that value in the total variable of the MRVS row.  It should be pretty straightforward but I can't update the total value shown on the row.  my onChange script works when I change the quantity but I need it work when i add the row, and trying to duplicate the code in an onload script didn't work for me. 

function onChange(control, oldValue, newValue, isLoading) {
	if (isLoading || newValue == '') {
		return;
	}
	var formatter = new Intl.NumberFormat('en-US', {style: 'currency', currency: 'USD', });
	
	if (isNaN(parseInt(newValue))) {
		g_form.setValue("quantity", "");
		g_form.addErrorMessage("Please provide an integer value for Quantity.");
	} else {
		g_form.setValue("quantity", parseInt(newValue));
		if (g_form.getValue("unit_price") != "") {
			var mrvs_total = parseInt(g_form.getValue("quantity")) * parseFloat(g_form.getValue("unit_price"));
			g_form.setValue("total", formatter.format(mrvs_total));
		}
	}
}

Thank you!