QuickSmelt is not doing anything to furnace smelt rates. I have set up the config properly, and it does nothing. I set "Use Permission" to false. Config looks like this: 

{
  "Use Permission": false,
  "Speed Multipliers": {
    "global": 20.0,
    "furnace.shortname": 1.0
  },
  "Fuel Usage Speed Multipliers": {
    "global": 20.0,
    "furnace.shortname": 1.0
  },
  "Fuel Usage Multipliers": {
    "global": 1,
    "furnace.shortname": 1
  },
  "Output Multipliers": {
    "global": {
      "global": 1.0
    },
    "furnace.shortname": {
      "item.shortname": 1.0
    }
  },
  "Whitelist": {
    "global": [
      "item.shortname"
    ],
    "furnace.shortname": [
      "item.shortname"
    ]
},
  "Blacklist": {
    "global": [
      "item.shortname"
    ],
    "furnace.shortname": [
      "item.shortname"
    ]
  },
  "Smelting Frequencies (Smelt items every N smelting ticks)": {
    "global": 0.05,
    "furnace.shortname": 0.05
  },
  "Debug": false
}
​

Smelting frequencies is an integer and should be 1 2 3 not 0.1

misticos

Smelting frequencies is an integer and should be 1 2 3 not 0.1

this does not seem right because years ago a 1 used to be vanilla rate as it stands this no longer is the case.
as it goes based off how much you smelt.. may need to take a look into the plugin again. as a 0=no fuel usage. 

Seems you can no longer do it like we once could which was having vanilla wood usage and charcoal while smelting 5x faster vice versa can't slow the fuel usage atm seems other then 0 which disables it completely..