A couple's tax bill was miscalculated repeatedly because of one inspector's bad judgment, the Ombudsman said yesterday. The couple complained to the Ombudsman about the department making repeated mistakes in over-assessing their tax liability. They had submitted their 1996-1997 tax returns in June and July of 1997 and asked the department to make a joint assessment of their incomes. However, when they received their assessments, they were five times above the correct amount. The department had not assessed their incomes jointly and the husband's part-time income was assessed twice - under profits tax and salaries tax - while the wife's assessment was without the married person's allowance. The same thing had happened to them in February 1997 and was resolved by the Ombudsman. On investigation, the Ombudsman found it was the same assistant assessor who made the mistakes. The Inland Revenue Department apologised to the couple and revised the assessment. It had warned the assessor. 'This is a case caused solely by personal misjudgment and carelessness. Much of the inconvenience would be avoided had necessary care and attention been paid in the course of assessment,' Wan Suet-ming, the Acting Deputy Ombudsman, said. 'But the office is pleased to see the department made quick amendments and I don't think this is a systematic mistake.'