Five years ago, Diamond Electric one of the divisions of De Beers paid $ 3.150,000 for diamond cutting tools. At that time, the company estimated an additional income of $ 500,000 to cover investments at 10% per annum. If there is an estimated service for more than 8 years with a residual value of $ 300,000, compare the required income all the time by the estimation of 5 years ago.