If a trustee determines that an allocation between principal and income required by section 7-749, 7-750, 7-751, 7-752 or 7-755 is insubstantial, the trustee may allocate the entire amount to principal unless one of the circumstances described in section 7-704, subsection (c) applies to the allocation. This power may be exercised by a cotrustee in the circumstances described in section 7-704, subsection (d) and may be released for the reasons and in the manner described in section 7-704, subsection (e). An allocation is presumed to be insubstantial if: [2001, c. 544, §2 (NEW).]