Can't evaluate an Item's class

I'm trying to calculate the amount of recurring vs. one-time revenue for an Order using the Class on the Item.

If an Item's class is Recurring, add to the Recurring revenue bucket on the Order.

I have this code, but the recurring variable is always zero and all revenue goes to the onetime variable.  The display name of the class is "Recurring."  What am I doing wrong?

[INDENT]for ( i = 1; i <= nlapiGetLineItemCount('item'); i++)
    {     
        rate = nlapiGetLineItemValue('item','rate',i);
        quantity = nlapiGetLineItemValue('item','quantity',i);
       
        if(nlapiGetLineItemValue('item','class_display',i)=='Recurring')
        {
            recurring = rate * quantity;
        }
        else
        {
            onetime =  rate * quantity;
        }

        totalRecurring += recurring;