Hello
Question - Why SAP does SAP recommend having copy of DDIC user for Support Pack work while we have DDIC available in the system?
Question to you:
Where did you see this recommendation ?
You can kick start patching with any user.
For SPDD you need to make sure that you use a user with the full authorizations other than DDIC as DDIC is not allowed to perform modification adjustments.
Read these links:
http://help.sap.com/saphelp_nw04s/helpdata/en/60/d6ba7bceda11d1953a0000e82de14a/content.htm
http://help.sap.com/saphelp_nw04s/helpdata/en/2e/6d66617d9011d396b60000e82de14a/content.htm
Additionally DDIC user is the only one allowed to login to the system during an upgrade.
http://help.sap.com/saphelp_nw70/helpdata/en/4f/3eaa7349aa2eb5e10000000a42189c/content.htm
http://help.sap.com/saphelp_nw70/helpdata/en/4f/40d6d6ed6a2eb3e10000000a42189c/content.htm
Regards
RB