S2417DG, G-SYNC, not working at overclocked 165Hz?

(This is a cross-post question from reddit /r/Monitors.)

Hi from South Korea. I've recently bought the DELL S2417DG (24" 144Hz 1440p G-sync, OCable at 165Hz) and so far I'm loving it. I've got the A05 revision (manufactured Jan 18). Color banding is there as I expected, but do not care much since I use it for gaming (I use U2718Q for other uses).

I need the official response from Dell regarding to the support for G-sync at Oc'ed 165Hz. It is a general consensus in Korean hardware communities (the largest one is coolenjoy, http://www.coolenjoy.net) that this monitor does not support G-sync at 165Hz. Usual monitors support G-sync up to their max refresh rate, but this particular monitor have failed to implement G-sync properly, so G-sync deactivates past 144Hz.

I wonder, is this true? Since I've not seen any articles in the west that depicts this "design flaw" of this monitor, Here in /r/Monitors and Overclock.net, Blur Busters, etc. Even one of the community member asked the Dell Customer Support (Korean) and received the answer that the official G-sync supported frequency range is 144Hz.

I've Personally experimented with 3 commonly used G-sync settings (http://www.coolenjoy.net/bbs/31/720694) (please use translator). The first video is a recommended setting from Blur Busters: G-sync On, NVCP V-sync On, In-game V-sync Off, and FPS cap to 162 (165Hz-3). The result is a total tear-free image.

But Some users commented that "This is because the traditional V-sync kicked in past 144FPS. I can feel the added mouse input lag past 144."

Can the moderator of this forum, or anyone here using this monitor cross-validate this? Is there any experiment, or review that pinpoint this? Any Discussions are appreciated. Thanks!

(Note: the second video setting is only G-sync On, and the third video is G-sync On, V-sync off (both NVCP & In-game), and FPS Cap to 162. Tearing occurs only at the bottom of the screen (Just like the one reported from Blur Busters) (https://www.blurbusters.com/gsync/gsync101-input-lag-tests-and-settings/2/)