SAP Proposed different user alocation

We know SAP recommend 3 System Landscape . Where there exist Development System , Quality System and Production System. And one extra system named IDES for learning system. Development is for Customizing all types of function as per business needs. Quality is for testing all type of configuration before going to Production System. This is for protect production environment from untested data. All configuration transport from DEV to QAS and then PRD by a Change Request Number using CTS system. In every system there can be different numbers of client. (Client is an concept to make independent , individual data environment using single Database, some data are client dependent and some are client independent. ) SAP proposed 6 clients in a Landscape. 3 are at DEV system , 2 at QAS system and 1 at PRD system.They are:

DEV: Test, Cust, Sand
QAS: QTST, TRNG
PRD: PROD

Sand: This is the client where Functional consultants do practice and check which need to be changed or unchanged.
Cust: This is the client where all changes(Customizing and Workbench) occurs.
Test: Here functional consultant and technical consultants do testing their change using data, they can create data also.

QTST: After transporting the testing team do integrated test in this client.
TRNG: This is for End user training.

PROD: This the client where business runs.

Users allocation
   
                       
          IDES: BPO, Technical Developer, Functional Consultant, BASIS
          Sand:  Functional Consultant , BASIS
          Cust:   Functional Consultant , Technical Developer, BASIS
          QTST: BPO, Technical Developer, Functional Consultant, BASIS
          TRNG: BPO, End User, BASIS
          PROD: BASIS, BPO, End user
Thanks