(2) B is the tax that would have been payable by the person if it had been calculated on the estimated value of the vehicle, for the purposes either of section 55.0.1 or of subparagraph a of subparagraph 2.1 or subparagraph b of subparagraph 2.2 of the second paragraph of section 17, reduced by(a) the amount by which that value exceeds the value of the vehicle as shown on the written estimate referred to in paragraph 3 of section 402.3, or
(b) the amount by which the value of the repairs to be made in respect of the vehicle as shown on the written estimate referred to in paragraph 3 of section 402.3 exceeds $500.