With the Lock status we can lock Masterdata,budget,account assignemt for the particular project.
TECO is the status susggest operational completion of the particular project we can do finanacial posing against the Object but we can not generate any PO/PR for the technically completed object.
CLSD is the status which susggest finanacial as well as techincal closure of the object once we achieve this we cant make any change in th objet.
All thse statuses can be reset.
1.Locked:-status stops u from making changes to project ... u have lock account assignment stops u from posting actuals to WBS ,lock planning , budgeting etc for WBS ,
2.TECO status means project is techanically completed and u cannot make changes to project but u can posting to project with TECO status.u can reverse teco again and make additions to projects and continue ... or using user status u can stop reverse TECO .
3. Clsd :-This is the final status of project after TECO for this ther should not be any balances left out in project related to actuals costs or revenues .Normally after settlemnet u can do this for project.U can reverse this status and can block the reversal thru user status.