Comment by cycomanic

I don't think it makes sense to talk about significant digits here. And while you are correct that you should not go from 999.9MB to 1.0 GB you are incorrect about your reasoning and your correction is also incorrect. Significant digits signify reliability of the numbers. So if your measurement is accurate to the +/- 50kB as indicated by 999.9MB you should then move to 1.0000 GB (5 significant digits). So it should be 10.00GB and 1.00GB not 1.000GB, because the reliability should not change between your measurements.