I did.
John at Digital Foundry - "Primarily [quality mode] aims for native 4k output. I found counting it that
1800p was the lowest that I found, sort of the lowest average. But it was also very close to hitting that 4k pixel count. But it can drop to
1296p in the rarest instances. I would say it's
not really representative of the actual normal resolution."
So mentioning "1200p" for Ratchet and Clank in the context of discussing Matrix demo is very strange to say the least, and it's virtually worthless as a data point comparison. It is far more often 4k than it ever will be in the range of 1296p.