If a trustee determines that an allocation between principal and income required by § 35-6-409, § 35-6-410, § 35-6-411, § 35-6-412, or § 35-6-415 is insubstantial, the trustee may allocate the entire amount to principal unless one (1) of the circumstances described in § 35-6-104(c) applies to the allocation. This power may be exercised by a cotrustee in the circumstances described in § 35-6-104(d) and may be released for the reasons and in the manner described in § 35-6-104(e). An allocation is presumed to be insubstantial if: