software Z=0 adjustment in firmware/host

Hi,
I'd like to suggest a simple "adjust z=0 level" feature for printers using Z_MAX endstop homing.
The leveling adjustment process on these machines is fairly simple in theory. When I notice that my first layer is printing to high, I'd just like to lower Z=0 by 0.05mm and try again.
In Repetier Host / Server this is done by editing the EEPROM and adjusting Z_MAX_LENGTH by +0.05mm and homing. Via firmware controls it is more complicated... I usually go to Z calibration menue, move to Z=-0.05, press "Set Z=0" and save to EEPROM.
Especially via the firmware this process is way more complicated than it should be, because it requires physical movement along the whole Z axis. Can't there be a simple "adjust Z=0 level" feature, where you can adjust Z_MAX_LENGTH by adding +/- 0.01mm increments and save?
This would really speed up my printing process, because adjusting Z=0 calibration is the most frequent type of adjustment on my printers