About DDR_MDIV1 bit on AM389x/C6A816x/DM816x.

Hello,

I have a question about DDR PLL of AM389x/C6A816x/DM816x.
In evm816x.gel, DDR_MDIV1 is set as 0x4.
But, Flying adder synthesizer 1 does not exist on TRM(SPRUgx8 : P204 Figure1-71 DDR PLL Structure).

Could you let me know..
 - Do I need set up DDR_MDIV1?
if yes,
 - Where does DDR_MDIV1 be set on DDR PLL structure? (How can I determine this value?)

Best regards,
RY