You are right. But this is the way EPA monitors it. It is the best way at this point in time to monitor the program. Is it perfect–Hell no! But the alternative is a full on Dyne test. Which is the correct way to measure emissions. But it would cost a whole lot more to implement to customers and shops. Right now a shop buys a NYVIP machine for the cost of approx (depending on options) $1,800. If they had to purchase Dyno’s the cost is in excess of $40,000. How much do you want to pay to get your car inspected?