ADF4193 register map query

I have a quick query regarding the ADF4193 register map. Unlike the ADF4351, the 4193 has registers of a differing number of bits (p.14 of D/S). However, I presume that as you write the control bits last due to the serial programming being MSB first that all registers are in fact 24 bits long otherwise it would be impossible to clock in registers of differing lengths if it is not known beforehand which register the data is destined for. Can somebody confirm this please?