Cant adjust Z probe height from menu

Bought a delta machine running on marlin. Everything working fine except i can not adjust the Z probe offset from the menu. The menu setting is there and reads correctly but when i click on it to adjust it it pops up with a strange number that is no where close to what it should be set at. And i can not adjust it to what it should be set to. My actual offset is .95mm, in the menu it shows -.95 but when i click on it to adjust it then it pops up with 0.5mm and i can not adjust it to a number less than .5. I assume there is a setting in marlin that needs tweaked but i have no idea where to find this at.

Edited 1 time(s). Last edit at 02/17/2018 12:18PM by GITRDUN.

Depending on the Marlin version you want to use, there is a section looking like that in configuration.h

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -(DELTA_PRINTABLE_RADIUS)
#define Y_MIN_POS -(DELTA_PRINTABLE_RADIUS)
#define Z_MIN_POS 0
#define X_MAX_POS DELTA_PRINTABLE_RADIUS
#define Y_MAX_POS DELTA_PRINTABLE_RADIUS
#define Z_MAX_POS MANUAL_Z_HOME_POS