P6 Actuals and Curves

Does anybody knows the difference between COBRA & PRISM when integrated with P6? How the actuals (straight from timesheets data)managed in P6 or maybe P7 in the future will do? And for sure the actuals was not really set up well directly to P6 when using other software for timesheet. And to date P6 could not produce the progress curves wherein showing the Earned Value, Budget, Actuals and Forecast Cost to complete? Maybe the curves could be done separately by using COBRA or a simple Excel presentation.