LC1 + Woolich logbox having a problem


I'm trying to do some tuning and I'm having a problem of AFR readings. the guage that came with my LC-1 kit reads ~2 lower then my logged afr. guage will read 11-12 while a log file will show 13-14. I suspect the guage is right and the logged afr is not accurate but not sure. I would like them to match...atleast close. Anybody else experienced this? Need some guidance from you editor pros, thanks.