As you know Windows incorrectly computes a linear VCGT curve as a result it uses 65280 max value instead of correct 65535. I was trying to fix it by using DispWin from Argyll but it's quite PITA, especially in multimonitor environment when you have to switch displays. And as a side effect, after correcting VCGT table your PC is no longer bitperfect (for example Calman's built in Dolby Vision pattern generator stops working). Is it worth to bother with it? I feel that differences during calibration between correct and incorrect VCGT are smaller than standard measurement error.