Hello Subudhi,
I could explain how SAP CAL calculates the cost forecast
According to https://aws.amazon.com/ec2/pricing/
r3.8xlarge with SLES costs $2.76 per Hour
r3.xlarge with SLES costs $0.433 per Hour
m3.medium with Windows costs $0.13 per Hour
SSD storage costs $0.10 per GB-month
Compute costs for 1 hour = $3.323
Compute costs for 8 hours = $26.584
Storage costs for ~574GB for 30 days = $57.4
Cost forecast for the next 30 days = $83.984
Best regards,
Stanimir