Hrrm can you add ANY other blocks from any other mod to the planks list to see if the config actually works at all whatsoever?
I have sadly no idea how this Mod works internally, so I would suggest asking the dev of that Mod how the Config works or if there is an error with how you wrote the entries.
You could try adding commas at the end of the lines and see if you are just missing those. Or Semicolons.