Wrong. The gom is also a rolling fuel calc. It's uses approximately the last 50km of driving history. You can see this 50km in graph form one one of screens of the touch screen. It is broken down into segments. I have watched the gom spike as inefficient segments at one end drop and are replaced by more efficient segments at the other end. I have watched the gom correct itself to my 20% reduced speed after 25-30km to make a detour.
The dic reports from when it was reset last. When's the last time you reset it?? Likely more than 50km ago so obviously they won't agree. You see those changes as your efficiency changes throughout the day.
Wrong, the GOM is not a rolling fuel calculation. Did you look at the WIND-WORKS article? You're objectively wrong and those numerous measurements show significant disagreement. Your anecdote does not contradict tables of numerous GOM and efficiency values (they do not agree, even when the car is brand new with basically no usage). Whatever GOM does, it's not a simple rolling fuel calculation like you think it is.
Not that it really matters, I've reset the DIC numerous times to test this. And I've done numerous tests to quantify battery capacity using kwhConsumed/diffSOC% to make sure my battery is actually around 66 kwh.
Why doesn't this DIC thing really matter? Because the Infotainment system will report miles driven and kwh hours consumed. You can simply divide the two quantities to get miles/kwh... no issue right? And these values reset when you recharge. That's definitely going to give you an accurate efficiency within - what you claim - the 50km history (my 32 mile total commute ~ 51 km). But they don't agree still! Oh, but how can that be?
NOTE: You make the bold assumption that the Infotainment's energy statistics is used by the GOM (it is almost certainly not used by the GOM).
Now, have you ever noticed that the Infotainment system will count backwards kwh consumed during regen? This directly affects your manual efficiency calculation from the Infotainment system... without kwh consumed counting backwards like that, my efficiency calculation would be far worse.
And that leads to my hypothesis: The GOM pessimistically measures only expenditures of energy and not regen to produce its range predictions.
If the Infotainment can count kwh consumed backwards during regen, then perhaps if it didn't, the measured efficiency would be in line with GOM's characteristically lower range predictions. It's a very simple explanation! On top of that, we all know the myChevy website/app would produce seemingly non-sense efficiency values (usually much lower). But these values (at least in my case), agrees almost exactly with the GOM. And they agree with my 75 mph commute (which SHOULD NOT be 4 miles/kwh).
And a nicety of this hypothesis (if true) is that it means the GOM is giving you driving range estimate assuming you never regen. This is the most conservative estimate you could possibly want, right? The GOM might be telling, "You can drive N miles if you never regen." And that makes a lot of sense to me.
Does my hypothesis explain your observation?
I have watched the gom correct itself to my 20% reduced speed after 25-30km to make a detour.
In fact it does! If you're reducing your speed, your energy consumption goes down. If the GOM only operates on energy expenditure to makes it prediction and you happen to be using less energy because you're driving slower, then that means GOM should provide higher range predictions.
And it explains my situation very well too! My commute is partly downhill. I drive 75mph for 20-30 minutes every day and I manage 4 miles/kwh through manual calculation from Infotainment (since you don't want to trust my DIC). How do I manage that? I am regenerating energy going downhill and my Infotainment system is counting backwards kwh consumed.
