I'm still having problems with the new version. The rates dont seem process right. I just put 1000 wood and 300hqm ore into a regular furnace, it lasted 1:43, burned through all the wood outputting 755 charcoal and 70 hqm. The only thing in my config adjusted is a global speed multiplier to 5x, and the extra default lines removed regarding furnace.shortname etc.
I tested with that config and was unable to produce the result you described. To test, I deleted the config file, reloaded the plugin to regenerate the config file, changed the global multiplier to 5.0, reloaded the plugin so it would detect the config change, placed 1000 wood and 300 hqm ore into a regular furnace, and turned it on. I tested with the 300 hqm ore in one slot, as well as spread across two slots. In both cases, it took approximately 5 minutes to complete (I didn't count it exactly), and both received 300 hqm and approximately 750 charcoal. If you are getting a different result, you may have another plugin conflicting.
If you are using the GitHub fork, please report any issues on the GitHub repo: https://github.com/WheteThunger/QuickSmelt/issues