Unless they have changed in recent history, the digitals were only guranteed to be accurate to +/- .2 of a grain. I have more faith in a balance beam scale being more accurate than that. +/- .2 (.4 possible from desired) grain seems like quite a lot of variation to me. That is almost half a grain.
Sometimes you get what you pay for, sometimes you only pay more for what you get.
Three shots are not a "group"...they are a "few".
If the Bible is the literal, infallible, unerring word of God...where are all those witches I am supposed to kill? (Exodus 22:18)