Originally posted by bibz The pixel shift technology isn't just taking 4 shots
It is, with shifting the sensor by 1 pixel in between shots. It stores 4 separate full images concatenatwd into a single file, like what a zip archive does.
BTW, HDR from multiple shots is the same exactly, provided you skip the second step of tone mapping. The result is deterministic and a raw file with added dynamic range, depending on separation of EV during bracketing. This is best seen by Lightroom 6's new capability to process an HDR bracket into a single raw with increased bit depth.
Moreover, modern sensors feature a full digital read out and there is much less happening in between reading the sensor and writing the file than you may think. And DxO's methodology includes to protect against processed sensor data, like averaging, tone mapping or black level subtraction. What they test is indeed the sensor output basically.
You can easily do the same with a Leica Monochrome: Have a revolving filter wheel in front of the lens with RGGB filters rotating during a burst of 4 shots. While such an accessory is easily doable, it wouldn't qualify the Leica Monochrome for a better DxO sensor score. Maybe, you can now accept why the pixelshift mode is a nice camera capability but must remain outside the domain of what is tested by DxO mark sensor.