Honestly, it looks pretty darned good already. I wouldn't worry about that bump at 15%. As you said, the DDC adjustment points are to either side of it, so not much can be done. Besides, can you really see a difference between 0.3 and 1.3 dE at that color and luminance level? Possible but doubtful. As to the program mapping more points to the 3D LUT than are measured, unless I misunderstand your question, this is entirely normal. With a 33x33x33 LUT, doing 1:1 readings would take a whole lot of time. On the other hand, sometimes the program will make more or less measurements than set by the user. I think this would depend on how many valid vs. invalid measurements the software is seeing during the display profiling. What I mean is that the display must fall into a certain performance envelope to be correctable by a 3D LUT. If some readings are outside that range, for whatever reason, I think the program might be taking additional ones in order to get a more accurate picture of the display's condition.I calibrated this evening the 65C8 of my good friend with a custom OFPS patch set optimised for rec709 colorspace. I aimed 100 nits so before AutoCal I set OLED light via DDC to 24 which results in ~125 nits. So the peak output drop after AutoCal is about 20% this is important to keep in mind.
After AutoCal I had to touch up some spots here and there manually to flatten things out.
I discovered the exact same problem I had with my C8 at 15 IRE with the little bump. I can't fix this manually because the 42p DDC control let me only adjust 13 and 16 IRE.
I also think that the TV doesn't load the LUT correctly because at 100% saturation the colors are off because of the wide gamut. It doesn't map rec709 it's wider. As you can see on my scans I ended up at 106% gamut coverage.
Another strange thing which I discovered is that CalMAN mapped 4-5 times the points to the 3D LUT during the measurements is that normal?
I attached also the cube after loading the 3D LUT into Lightspace and I discovered that 2 yellow points are way off - same with mine C8 maybe Tyler can say something in addition to that.
I know that pictures from the phone aren't really reliable but they show pretty impressive how good this "small" patch set works instead of 3000 or even more iRP LUTs.
Hope that portrait displays is going to improve the algorithm further.