Not sure if allowed, but I made some changes to add a fix for electric furnaces. They toggle on and off now with the Turn On GUI button and are quicker in speed based on speed multiplier in config.
https://drive.google.com/file/d/1QiSr00Tnlz2t71LBAn651rBtI2vC7-bv/view?usp=sharing
Just download the file I uploaded there, copy the source, paste it in your current QuickSmelt.cs file and save - or remove the previous QuickSmelt.cs and drop the new file in. Reload the plugin with oxide.reload QuickSmelt
This works with default config so no changes need to be made to your current config if you're using global multipliers. If you'd like to add modifiers for just the electric furnace, add a new listing for it in the config file under "Speed Multiplier" option and other options as needed:
"electricfurnace.deployed": 1.0