[dBC]

There is an ECO mode that really deadens the throttle response, but you've already ruled that out by saying it's in Sport mode. Having the speed limiter engaged is another possibility - it starts to ramp down power well before you get to the set-point.

At 40% SoC full power should be available. It's only when it gets right down near empty that it starts reducing available power. Does the MAX POWER gauge reveal anything? It tells you how much power is on-tap ready to be used. It should almost always be on full (right around past the 'R' in POWER) except in extreme temperature conditions, or extremely low SoC. It's the blue arc above the fuel gauge:

When I first start mine in the morning, it starts off one or two notches below full as shown in the pic below, but it brings it back up to full before I've backed out of the garage - presumably as it warms things up:

 

[dBC]

Yeh, you really need to be in ECO mode to experience the dead performance. That said, I think there is a slight difference in performance between Sport and Comfort but it's very subtle. A hard launch in Comfort mode will briefly chirp the tyres in mine whereas in Sports mode it doesn't. I reckon you'd know if there was an entire motor out, but if you want to see when each motor is being used you can pull up the EQ->Energy Flow screen:

I take it the Power Meter mentioned earlier didn't reveal anything?

The switch under the accelerator pedal is an emergency override for the speed limiter. My regular drive includes a bunch of suburban 50km/hr roads that takes me to T on a dual carriageway. I'll have the limiter set to 50 on the suburban streets. If I forget to disengage it (or flip it higher) it can sometimes get exciting when I turn onto the dual carriageway. I get this dead throttle as the car reaches 50km/hr... you can push it all the way to the floor and it won't exceed 50 and all the while the truck in the rear view mirror is getting closer and closer. You can either quickly remember how to disengage it, or you can press the accelerator pedal further into the floor to activate that switch. Be warned though - it totally launches when you do, so don't do it too close to a car in front.

Excerpt from the owner's manual:

 

[dBC]

Do you have the integrated dashcam? It's actually a pretty painless way of timing your performance. The video is is at 30 fps and the speed stamp gets updated 10 times per second, i.e. every 3 frames. So if you play the footage back on your computer one frame at a time, you can see exactly what is gong on down to a resolution of 1/10th of a second. I set t=0 to be the first frame where I could see the bonnet start to lift and ended up with a plot like this:

 

[dBC]

How long does it take to do 0-100km/hr? Should be right around 5 secs.

 

[dBC]

For kicks I re-did the above experiment but this time in Comfort mode. Curiously, it came in a little faster at 4.7 secs 0-100km/hr indicated. My speedo under-reads by about 3km/hr at that speed so 0-103 took 4.9 secs. The car is a year older, different set of tyres, different stretch of road and different weather conditions.

I guess the only conclusion to draw from that is that, like you, I don't notice much difference between Sport and Comfort mode in full-throttle launches. And without some sort of timing device, I wouldn't notice any difference at all.

 

[dBC]

That is an interesting one - sounds like you've already eliminated the most obvious causes. Maybe you could ask the dealer to give you a battery State of Health reading. That's about the only other thing I can think of.

 

[dBC]

It's almost as though the 'max.power' gauge on my car is showing how much of the potential EQC's power it is currently using/applying

There is actually a dial for that that you can bring up on the RHS area of the instrument cluster. When cruising on flat motorway at 110 km/hr, mine usually hovers around 10%:

 

[dBC]

Very interesting. Thanks for updating us all. I wonder what the adaptation process involved.