Agreement on deductions from salary or other incomes – still a contract to the weight of the third person?

Act No. 89/2012 Coll., Civil Code, as amended (hereinafter „Civil Code“), brings substantial change of the legal regulation of agreements on deductions from salary or other incomes. The Civil Code left in § 2045– 2047 the previous conception of agreement on deductions from salary or other incomes as a contract to the weight of the third person.
The temporary regulation in § 3073, the 1st sentence of the Civil Code can seem as problematic, because it makes possible the existence of two groups of agreements on deductions from salary or other incomes, both of them with other legal regulation, on the one hand the newly closed agreements according to the Civil Code, on the other hand the agreements closed according to the previous legal regulation, where the debts have not been fulfilled yet.
Considering § 2, subsection 1, the 1st sentence of the Civil Code there is a question, if the temporary regulation in § 3073, the 1st sentence of the Civil Code is consistent with the Constitution, when after coming into force of the Civil Code it makes possible to ask for executing deductions from salary or other incomes according to the previous legal regulation, it means on the basis of contracts to the weight of the third person.