Solution:
We need two parameters from win-client to send mails automatically from win/web.
1. Send approval mails when CSR workflow approvals are generated. It should be Yes.
2. Delay workflow approvals until all other rules satisfied. This flag should be unchecked in the Approvals tab of System Maintenance table.
With these settings in place automatic mail is sent, once the approver approves from the email, the SCA receives the response, then move the Workflow status to the next step if the Auto-Advance is set.