Light Meter Calibration

Working in a studio with a friend few days back I realised that both our light meters were reading the same light differently. I was wonderstruck and felt that either one of the meters is defected. We chose to pick a new meter which was Sekonic L308B and its reading matched my friends light meter readings and then it was obvious for me to doubt mine.
Sekonic’s representative told me over an e-mail that it is possible for the meters to read same light differently and difference by even half a stop could be considered as normal and advised that anyone using a light meter should insist on using a grey card and bracketing an exposure can assure one that he/she lands safe in ballpark. Apparently I found the Sekonic Profiling Target II at B&H and did the complete procedure. In my observation, my meter’s reading got corrected by one tenth stop. I find it extremely difficult to trust my Camera’s LCD as it might just end up showing the image brighter than what it possibly is. In such a scenario I choose RAW + JPEG format where I have enough latitude in my images to have a safe landing.
Coming back to LCD brightness, my learning says that the brightness of any screen should be equal to the ambient light where the screen is placed. For the same reason I use a Nikon D800 because it has an ambient light sensor which helps it adjust the brightness automatically. This principle also applies to the display of your workstation. Understanding all this is extremely important if a person wants perfect output of his/her photographs.