Sony S-log picture profiles trigger ISO override and compensate for the resulting lower raw data values by applying a suitable tone (gamma) curve.
When the camera is set to ISO 3200 the actual taking ISO is around 400 (you can see that in the Makernotes, at least for the raw files). Here is an example:
EXIF ISO : 3200 MakerNotes Sony ISO : 384 MakerNotes Stops Above Base ISO : 1.9
Here the actual taking ISO setting is 384, 3+ stops lower than the one that was set on the camera. Leaves plenty of room for highlights, midpoint in this case is below 2% instead of the usual ≈12.6%
You can take a shot of a gray card and analyze the raw data to be sure of the midpoint offset.