(1) This subpart 7 shall govern the ascertainment of income and principal and the apportionment of receipts and expenses between tenants and remaindermen in all cases where a principal has been established with or, unless otherwise stated in this subpart 7, without the interposition of a trust; except that, in the establishment of the principal, provision may be made touching all matters covered by this subpart 7, and the person establishing the principal may himself or herself direct the manner of ascertainment of income and principal and the apportionment of receipts and expenses or grant discretion to the trustee or other person to do so, and such provision and direction, where not otherwise contrary to law, shall control notwithstanding this subpart 7.

(2) If neither this subpart 7 nor the direction of the person establishing the principal states an applicable rule, income and principal shall be determined in accordance with what is reasonable and equitable in view of the interests of those entitled to income as well as those entitled to principal and in view of the manner in which persons of ordinary prudence, discretion, and judgment would determine such matters. If the person establishing the principal grants the trustee or other person discretion in crediting a receipt or charging an expenditure to income or principal or partly to each, no inference of imprudence or partiality arises from the fact that the trustee or other person has made an allocation contrary to the provisions of this subpart 7.