LT8640 Thermal Resistance Values

The datasheet for LT8640/LT8640-1 lists theta_JC(PAD) = 12 C/W.

First, I would like to confirm that this represents the junction-to-board thermal resistance. Typically, JC denotes junction-to-case, however, in this case it calls out the PAD which makes me believe this value is supposed to be for the junction-to-PAD which is soldered to the PCB.

My follow-up question is what is the complimentary thermal resistance to the value above? What ratio of heat is expected to go towards the board vs towards the top of the component? 

All responses are appreciated, thank you!