Yes it is possible to calibrate an HDR display. However, it is totally different than what we were accustomed to with REC.709 calibrated because the TV is setup by default to come close to its full capabilities. Well atleast that is the case with the Vizio P-series and the "Calibrated Dark" profile. Since the TV has some tolerances and inherit variances you can calibrate those out. The benefits of calibrating a properly configured HDR display are minimal at best. Almost definitely not worth the cost.Your post makes sense, except I have asked several times in the calibration and HDR/WCG threads whether it is even possible to "calibrate" current HDR10 only sets to either dci.p3 or rec2020 and have, several times, been told "no" its is not currently possible to calibrate, because, essentially, each set simply "does what it does" when HDR mode kicks in. If you have contrary information, I would love to see a link, as I and trying to get my head wrapped around this issue before I purchase my next display. I freely confess that I don't have a handle on this issue as much as I'd like to.