I stopped using power play tables since 18+ drivers. overdriventool is enough to achieve full hashrate at 165W with vega 64 and modified vega 56.
clock: set to 1600, voltage set to 850mV
mem: set to 1100, voltage set to 860mV
real clock is 1400 to 1500 depending of the card ; real voltage: 885 mV; shown in GPUZ.

4 cards rig is at 700W, system uses roughly 35W