The Dual Layer DVD+R discs I bought say they hold up to 8.5 GB of data. However, when I burn a disc with Toast 6.09, Toast says that only 8 GB are available, and in reality, Toast will only let you burn 7.9 GB: if you have 8 GB of data it will tell you that 8 GB are needed! Anyone have any clue what the deal is here?