Actually yes the "MORDOR_LUMBERMILL_MONEY_AMOUNT" (and the timing one too) is unused but it's competly possible to change the money you earn from chopping trees
to change that you need to edit that line in gamedata "ValuePerSupplyBox" (by default it's 5)
but strangly in bfme1 you get the value you choose multiplied by 3 (so with 5 u get 15) wich is kinda annoying (by the way rotwk don't have that problem at all)
to fix this u will need to work with the "ValueMultiplier" in the Lumbermill code (in the SupplyCenterDockUpdate), for exemple i wanted to get 10 money with lumber so i set 5 in the gamedata wich should gave me 15 ingame and then set the ValueMultiplier to 0.67 to get 10 (well as close to 10 as possible)
Edited by Miraak5, 02 May 2019 - 02:13 PM.