Time & Material Model becomes a good option when scope, specification and implementation plans of a software development project are not feasible to define. Under this model, customers pay for the hourly development efforts put in by the developer. Under this mode ACE works hand in hand with the client for execution of the project from start till end.
Couple of times once the scope is frozen the time and material project also gets converted to the fixed price model. We have strict project management and reporting practices for T&M model wherein the timesheet is sent to the customer for approval for the number of hours the developer has put for the project.