Hi Marc,
Can you show me a screenshot of the amount that APP reports, and the the number of Bytes, KiloBytes, MBs or GBs your OS reports?
I have just checked on my Windows desktop and my Macbook 2016, within rounding and taking into account that
1GB = 1024MB = 1024x1024kB = 1024x1024x1024Bytes.
the number reported by APP is accurate on my systems.