The cause of this confusion is the view in terms of persons instead of functions. The three functions in process control are planning, monitoring and diagnosis. The process or task is goal directed. The execution has to do with the planning of actions. The plan is executed and the execution is monitored.
Monitoring means that actual results are compared with planned results.
If there is a discrepancy between actual and desired outcomes diagnosis has to take place to find out what the causes of the discrepancies are and what kind of remedial should be given. A characteristic of coaching is that the tasks are performed by the student as well as the coach. The planning function in an ITS is in most cases fixed. It is a kind of desired course of action. An ITS needs an explicit strategy.