Assuming custom cards use the same voltage controller which they should), this software should be compatible with custom RX 480's like the Sapphire Nitro as well correct?
Yes it should work - but to be safe first check if all values displayed actually make sense before trying to change them. Also I would love to see an I2C register dump and screenshot before calling the non reference boards 'supported'.
Sabertooth 990 FX R 2.0 FX 8120 BL ED. B2 Rev Can over clocked to 5.0( Normally run at 4.4 Ghz ) 2 x 8 Gb Corsair Vengence 1600 Ram EVGA Supernova 1050 GS Gold PSU Logitech G502 Proteus Gaming Mouse Powercolor PCS+ R9 290X x2 CM Storm Trooper Case SteelSeries Apex Gaming Keyboard SteelSeries Stealth Merc Keyboard (1 broke key) Several Sata HDs CM Seidron 120 AIO Closed Liquid Cooler Disabled so not a ton of money.