// Travel limits after homing
#define X_MAX_POS_DEFAULT 450
#define X_MIN_POS_DEFAULT 0
#define Y_MAX_POS_DEFAULT 355
#define Y_MIN_POS_DEFAULT 0
#define Z_MAX_POS_DEFAULT 310
#define Z_MIN_POS_DEFAULT 0


#define X_MAX_LENGTH (base_max_pos[0] - base_min_pos[0])
#define Y_MAX_LENGTH (base_max_pos[1] - base_min_pos[1])
#define Z_MAX_LENGTH (base_max_pos[2] - base_min_pos[2])

I'm going to print the function and see if I can find a problem.