ADC128S102: 0.8 MHz "typical" given for f_sclk(MIN)

Hello,

f_sclk(MIN) is specified as min 8MHz and f_sclk is specified as max 16MHz in the ADC128S102 datasheet. However, there is a 0.8MHz "typical" value stated for f_sclk(MIN). What does this mean?

We need to drive this ADC at 4MHz. If that is not within spec, are any other devices in this family, e.g. ADC128S022 or ADC128S052 with lower clock speed requirements considered drop-in replacements in terms of physical package and serial command structure? The conversion rate of either of those devices would work for our application.

Thanks