Gareth 32

This has been a very interesting thread. I never heard of Dual ISO and almost thought it was an in-joke (like "blinker fluid" for cars). To return the favor, I found this awesome video that explains the details, but you will need at least 2 or 3 cups of coffee to keep up:
 

if the OP is interested in getting information about the X-S10 I'd suggest getting involved and post data to Bill Claff at the Photons to Photos web site so that he can include it in his results

Thank you jerryy

It would already have it most likely. That is not really a direct user setting, just something the internal software switches on or off depending on what the user set iso, shutter speed, ev comp, aperture, etc are doing. The X-T3 switches at ISO 800.
Fujifilm sensors tend to be ISO invariant so that also plays into when the switch is made.

The X-S10 sensor is very close to the one in the X-T4, so keep an eye out for any X-T4 results and your X-S10 should be very close. This site publishes listings for various camera bodies, hut has not yet been updated for either of those two:
https://photonstophotos.net/Charts/PDR.htm#FujiFilm X-T3

Probably the autofocus or IS system of the lens.