Wages upon which tax is required to be withheld shall be taxable under this chapter as if no withholding were required, but any amount of tax actually deducted and withheld under this chapter in any calendar year shall be deemed to have been paid to the tax commission on behalf of the person from whom withheld, and such person shall be credited with having paid that amount of tax for the taxable year beginning in such calendar year. For a taxable year of less than twelve months, the credit shall be made under regulations of the tax commission.