Following on from Miki's post above, I spent quite a bit of time testing this new feature over the weekend (sorry it's taken a while to leave feedback)
and I concur with Miki's assessment.
In my case, I ran the new Grey Scale Plus sequence a total of 6 times to check the results were repeatable, which they were.
Tests were performed on an LG OLED65C9, starting from unity 3D LUT and peak 109% white pre-calibrated to my target white point, and panel native gamma response. Below are two screenshots from 1000 point verification profiles of two of the resulting calibrations, one targeting Rec709, D65, 2.4 gamma, and the other targeting Rec709 with an alternate white point and 2.4 gamma.Rec709 D65Rec709 AWP
As it happens, I had actually reprofiled my C9 on Friday evening with a full volumetric custom patch sequence, and using Miki's excellent spreadsheet, here is the summary of the results from that calibration.1000 point verification of a volumetric display profile The results of the Grey Scale Plus LUT when verified with 1000 points
Pretty impressive from just 27 measured points, and visual verification with test patterns and real content is just as impressive with no banding or other artefacts that I have been able to find as of yet.
Of course, a full volumetric profile gives you the confidence and certainty that you display will be calibrated to it fullest potential, but for a quick calibration (it takes literally a couple of minutes) it produces highly impressive results.