1026.37(o)(4)(ii) states: The percentage amounts required to be disclosed under paragraphs (b)(2) and (6), (f)(1)(i), (g)(2)(iii), (j), and (l)(3) of this section shall not be rounded and shall be disclosed up to two or three decimal places. The percentage amount required to be disclosed under paragraph (l)(2) of this section shall be disclosed up to three decimal places. If the amount is a whole number then the amount disclosed shall be truncated at the decimal point.
If the TIP rate is has three decimal places, it should be shown to three decimal places. If it only has two, then you would only show two places. If there are more than three decimal places then you would truncate it at three decimal places.