How can I change resolution and Scalability same time

I want to do a quality setting for game. The player can custom their setting like resolution or Scalability settings. but if I execute the all setting like following code. it will just change the resolution.but not any Scalability setting

//Resolution
FString Resolution_CM = TEXT("setRes 1024x768");
ConsoleCommand(Resolution_CM, true);

//ScreenPercentage
FString ScreenPercentage_CM = TEXT("r.ScreenPercentage 100");
ConsoleCommand(ScreenPercentage_CM, true);

//Anti-Aliasing_Quality
FString PostProcessAAQuality_CM = TEXT("r.PostProcessAAQuality 1");
ConsoleCommand(PostProcessAAQuality_CM, true);

//TextureQuality
FString TextureQuality_CM = TEXT("sg.TextureQuality 1");
ConsoleCommand(TextureQuality_CM, true);

//Effects_quality
FString EffectsQuality_CM = TEXT("sg.EffectsQuality 1");
ConsoleCommand(EffectsQuality_CM, true);

//PostProcessQuality
FString PostProcessQuality_CM = TEXT("sg.PostProcessQuality ");
ConsoleCommand(PostProcessQuality_CM, true);

//ShadowQuality
FString ShadowQuality_CM = TEXT("sg.ShadowQuality ");
ConsoleCommand(ShadowQuality_CM, true);

//MaxFPS
FString MaxFPS_CM = TEXT("t.MaxFPS ");
ConsoleCommand(MaxFPS_CM, true);

This guy seems to have had the same problem with a possible fix: