The API allows you to set shutter speed in milliseconds or as a percentage. The specs on the MLX list shutter speeds of 0.3 μsec ~ 10 sec. I assume that 100% exposure is not set to be a 10 second shutter speed.
So how do the two map, roughly? (For the MLX in particular)
The maximum exposure time is limited by the DUO frame interval and it is always shorter than the frame interval itself.
This is because the sensor pixels are first exposed all at once (global shutter) and then the image data is being transferred.
So: frame_interval >= exposure_interval + frame_transfer_interval