Dorothy has just heard a model definition. The comic tells you what it is all about. If you look at what accounts do, ideal tax may also mean tax calculated by somebody else. Ideal cash flows may mean a cash flow statement prepared by someone else. And what happens if an accountant does something by himself/herself and at the same time somebody else does the job? Such paradox in the expert system is accessible at this link. The online system with the accountant?s hands checks independently what the accountant has calculated.