Section 6-612. Recognition of order modified in another state. A tribunal of the commonwealth shall recognize a modification of its earlier child support order by a tribunal of another state which assumed jurisdiction pursuant to a law substantially similar to this chapter and, upon request, except as otherwise provided in this chapter, shall:
(1) enforce the order that was modified only as to amounts accruing before the modification;
(2) enforce only nonmodifiable aspects of that order;
(3) provide other appropriate relief only for violations of that order which occurred before the effective date of the modification; and
(4) recognize the modifying order of the other state, upon registration, for the purpose of enforcement.