symbios=MacPro6,1: Do I still need to patch to get Night Shift working?

According to this document (https://pikeralpha.wordpress.com/2017/11/06/supported-mac-models-for-night-shift-in-high-sierra-10-13-2/), the minimum version for Night shift on a MacPro is 6,1 and mine is already that.

But when I looked at the display setting, there's nothing there.

Perhaps OSX detects my Dell monitor is unsuitable for Night shift?

Thanks