If a trustee determines that an allocation between principal and income required by § 62-7-918, 62-7-919, 62-7-920, 62-7-921, or 62-7-924 is insubstantial, the trustee may allocate the entire amount to principal unless one of the circumstances provided in § 62-7-904(C) applies to the allocation. This power may be exercised by a cotrustee in the circumstances provided in § 62-7-904(D) and may be released for the reasons and in the manner provided in § 62-7-904(E). An allocation is presumed to be insubstantial if:

(1) the amount of the allocation increases or decreases net income in an accounting period, as determined before the allocation, by less than ten percent; or

(2) the value of the asset producing the receipt for which the allocation is made is less than ten percent of the total value of the assets of the trust at the beginning of the accounting period.