Phase costing takes accounting to the next level. Phase accounting (costing and accounting are interchangeable at this level of detail) can only be used with job costing. It is designed to break a job down into distinct functions (stages) for analysis. It is a tool to identify discrepancies from estimates.
Project accounting is one of the several different sub-types of managerial accounting. Project accounting is used to provide a feedback loop on production issues related to large scale set of complex functions. A good example of project accounting is the financial outcome related to the construction of a hospital, the erection of a tower or installation of a manufacturing process system.