we can give only rough estimates, we cannot give exact numbers like 250 GB savings,
its only a rough calculation (approx upto 250 GB) space savings ...that can be provided.
why? because each archive object has different size calculations.
SARA Statistics and spools can help mostly , but also in some cases like IDOC
if you look into an IDOC archiving statistics, the stats are misleading
note: 1513137 - Archive object IDoc - Summary statistics are misleading
cos we are dealing with a cluster table here -EDI40
see the steps in Resolution of this note and you will find some answers
