THERE are many theories about tax leakages. One big source of leaks is tax evasion, and another is collusion between taxpayers and tax officials. No question, these leaks happen because of the weak oversight within the tax department. But Director-General of Taxes, Hadi Purnomo, 58, denies this. He insists that the internal oversight system actually works. As proof, he cites more than 1,000 tax employees who have been disciplined because of their