Except to the extent otherwise provided in the governing instrument, the following provisions shall apply to a trust which by its governing instrument requires distribution of a unitrust amount (whether payable in a single sum or in installments), such trust to be referred to as an "express unitrust":
(1) The income and net income of an express unitrust is the unitrust amount, but only if the unitrust amount is not less than three percent and not more than five percent of the net fair market value of the trust assets. If the unitrust amount is more than five percent of the net fair market value of the trust assets, the income and net income shall be five percent of the net fair market value of the trust assets, and the excess over five percent shall be considered to be principal of the trust.
(2) Expenses which would be deducted from income if the trust were not an express unitrust shall not be deducted from the unitrust amount.
(3) The trustee, from time to time, may determine the following:
a. The frequency of payment of the unitrust amount during the year;
b. Any adjustments to be made to the unitrust amount due to other payments from or contributions to the trust;
c. The valuation dates to use;
d. How nonliquid or hard to value assets shall be valued, how frequently to value them and whether to estimate their value;
e. Whether to omit from the calculations the value of trust property occupied, used, or possessed by a beneficiary; and
f. Any other matters necessary for the proper functioning of the unitrust that are not inconsistent with the governing instrument.