Are you referring to the “Monthly Principal and Interest” in the Loan Terms table per 1026.37(b)(3)? If so, I agree that the regulation and commentary to 1026.37(o)(4) states that an amount is not permitted to be rounded unless 37(o)(4) specifically requires an amount to be rounded. 37(o)(4) does not mention rounding of the “Monthly Principal and Interest” to be disclosed per 1026.37(b)(3).
Paragraph 37(o)(4)(i)(C) and its commentary does allow rounding of the total monthly payment (under the Projected Payments Table) in some circumstances. See the commentary below:
Section 1026.37(o)(4)(i)(C) requires the total monthly payment amount disclosed under § 1026.37(c)(2)(iv) to be rounded if any of its components are rounded. For example, if the total monthly payment disclosed under § 1026.37(c)(2)(iv) is composed of a $2,000.49 periodic principal and interest payment required to be disclosed by § 1026.37(c)(2)(i) and a $164.49 periodic mortgage insurance payment required to be disclosed by § 1026.37(c)(2)(ii), the creditor would calculate the total monthly payment by adding the exact periodic principal and interest payment of $2,000.49 and the rounded periodic mortgage insurance payment of $164, round the total, and disclose $2,164.