I just picked up a used scale on ebay. It powers up and does everything it seems like it should. Read the manual, and tried to scroll to the GN option to measure in grains. It is not an option. I have read the manual back and forth, and cannot find the setting. I reset the scale to factory settings and it is just not there. Did I get a version of the scale without it? I could not find any reference to different versions. I am not using the trickler or anything else. Just trying to get it to read in grains. Any help appreciated.