If a trustee determines that an allocation between principal and income required by KRS 386.480, 386.482, 386.484, or 386.486 is unsubstantial, the trustee may allocate the entire amount to principal. An allocation is presumed to be insubstantial if:
(1) The amount of the allocation would increase or decrease net income in an accounting period, as determined before the allocation, by less than ten percent (10%); or (2) The value of the asset producing the receipt for which the allocation would be made is less than ten percent (10%) of the total value of the trust's assets at the beginning of the accounting period.