Steps per mm on z axis to be added in setup of the machine

i wolud find it very useful if we could enter the steps per mm for the z-axis as option beside the 8mm and ACME rod
as the setup always changes my values ( for 0,9° stepper and 1/8 microstep)
i now configured the x-controlle in halfstep to go along with the values obtained in setup by choosing Acme rod