Audit planning

Yes, audit planning is at a very early stage. However, if your plan was to use ToC and you found that the controls were actually poor, then you would to some extend have to revisit and amend your audit plan. Or, when carrying out your audit you discover something else important (like a whole new factory they had forgotten to tell you about), the plan would have to be changed.

The process of planning: risk assessment: audit evidence etc is not always simply linear.