So I couldn't find any concrete information this.
From what I understand, KFZW is used for ignition timing (in my case KFZW2 is set to the same values as I have an earlier engine without VVT).
We also already have the optimal timing map (KFZWOP) for our engines (assuming gasoline and lambda 1).
I understand that we are somewhat limited for advancing timing at WOT by knock, but why not advance the lower load areas?
I use my car daily and I spend many miles cruising, sometimes at 4k rpm and it hits 5-10 psi when going up long slopes. My EGT gauge also registers up to 850C during these light climbs (usually around 750-790 when cruising at higher speeds).
Would it not lower my EGTs and improve efficiency if I was to advance the lower load areas up to the values in KFZWOP? I always use 99RON fuel so I am not expecting to see knock (though I always keep an eye out for it in the logs)?

Am I missing something?

So isn't kfzwop the timing for maximum torque/efficiency?
Therefore copying values from kfzwop into kfzw at lower load areas would improve efficiency at cruise/part throttle?

If they've tuned for the lowest common fuel, there probably is a bit to be had if running on a better fuel. That's engine efficiency though, doesn't take the extra cost into account.

My Mk6 R is averaging about 5mpg (imperial) more on the commute with the same roads, same traffic and (unfortunately) same shit cold weather. Just with cam and ignition advance.

No, I fully advanced the cam in the low load areas and then threw in timing until I started seeing flickers of CF, then pulled out 3 degrees. On average, I've added on average about 7.5 degrees in my low load, low speed (moving off, street speed load areas) and about 4.5 in the cruise (50-90% load, 2.5-4k). In those areas there's also another 8-10 degrees of intake cam advance as well.