src/Tasks/ShopMigrationTask.php
public function migrateOrderCalculation($order)
    {
        if (!is_numeric($order->Total) || $order->Total <= 0) {
            $order->calculate();
            $order->write();
        }
    }
public function migrateOrderCalculation($order)
    {
        if (!is_numeric($order->Total) || $order->Total <= 0) {
            $order->calculate();
            $order->write();
        }
    }
Performs calculation function on un-calculated orders.