Hello Aaron.
ADCK signal is taken after the clock divider module as shown below:

The complete block diagram is in 23.2.2
I think the example 23.5.4.6.2 it's wrong, the total conversion time it's:
ConversionTime = SFCAdder+AverageNum(BCT+LSTAdder+HSCAdder)
ConversionTime = (3ADCK+5BusK)+32(34ADCK+20ADCK)
ConversionTime = (3/1MHz +5/8MHz)+32(54/1MHz)
ConversionTime =1.731ms
Regards.