At the time of filing the last business tax return for the year, dual-status business entities shall adjust the tax due based on the non-deductible ratio for the current year, and report the adjusted tax in the last business tax return for the year. The formula is as follows: 
Adjusted tax = Input tax already deducted for the year - (input tax for the year - non-deductible input tax pursuant to Paragraph 1, Article 19 of the Act) x (1 - non-deductible ratio for current year) 
If the dual-status business entity has purchased any of the services specified in Paragraph 1, Article 36 of the Act, the relevant business tax shall be adjusted according to the following formula: 
Adjusted tax = Payment for services purchased in the tax year x applicable tax rate x non-deductible ratio for the current year - business tax already paid for services purchased in the current year
If the dual-status business entity starts business during a year and its actual operation time in the year is less than nine months, the said business entity is not required to make a tax adjustment for the current year. The entity shall make an adjustment according to the preceding two paragraphs while filing the last business tax return for the following year.