I would suggest setting the mod settings values Factorio defaults at the beginning, maybe also said in the tooltips.
I can see now that walls hp modifier currently starts as 5 and repair speed 10, but those are multipliers, not something like 5% and 10% but x5 and x10! I was only expecting to change just 1 value; the wall's HP and leave resistances and all else to defaults.
Also reference page https://wiki.factorio.com/Wall
