Overpaid tax can't be offset by next year tax. They treat each year separately, can't just use last year credit to offset this year taxable amount.

Means that if 2005 you overpaid Rm100 and this year your tax is 1,000, you still need to pay 1,000 first then file a claim back of previous 100. You can't just pay 900. If you pay 900, they will treat as underpaid and can be penalised.