https://mods.factorio.com/mod/ConfigUnderLengths
Never claimed to be a one of a kind mod. There are several out there that modify length. That being said, I have 2 extra tiers of each belt and pipe and they are setting configurable for underground length. The cost also scales and they have a unique icon which the mod you link does not do.
I made this mod for myself as I wanted to have non-cheaty options to go underground further, primarily for having less entities on the map and for convenience. However, it's balanced as you pay for it in game with scaling costs.
Anyone is free to use this or another mod of course. Whatever works best for you.
