Almost 1,5 year after, the Exchange Team released an update for the Exchange 2010 Server Role Requirements Calculator. The updated version is 20.9 and contains minor bug fixes over the previous version.

Fixes since version 20.8:

• Additional fixes on CAS/HT CPU calculations formulas
• Disabled Distribution tab for Active/Active Single DAG model
• Added Distribution tab warning that only one of the two DAGs is shown
• Fixed RAID disk calculation for A/A scenario and lagged copies

You can download the calculator here. For more information please consult list of changes here or view usage instructions here.