Understand sum of key-value sizes

Using FoundationDB
1

Hi, I’m trying to understand how sum of key-value sizes from fdbcli status is calculated.
When checking on my fdb cluser I’m getting: Sum of key-value sizes - 539.057 GB
But when I call GetEstimatedRangeSizeBytes with AllKeys subspace I’m getting ~96.7Gi
What am I missing?
Does AllKeys subspace covers all the subspaces in my db? does it includes system keyspace?

Also, when I checked for fdbbackup status I found that:
RangeBytes written - 46330839148
which can explain more ~46Gi, but the gap is still very big.

How sum of key-value sizes is calculate? and how can I find the missing data stored in fdb?

Thanks!