Recently, I noticed that MMS always uses the following units to refer to data size:
MB (megabytes)
GB (gigabytes)
TB (terabytes)
etc.

A good example is within backup, where we show you how much storage your snapshots consume and how much oplog data has been processed. In our calculations, we use the following conversions:
1 MB = 1024^2 bytes
1 GB = 1024^3 bytes
1 TB = 1024^4 bytes

However, this is not correct; these units are actually defined as:
1 MB = 1000^2 bytes
1 GB = 1000^3 bytes
1 TB = 1000^4 bytes
(see here)

This is a common source of confusion and should be clarified on our FAQ.