To enforce an out of state child support judgment, is a formal motion to register it required?

In Texas the father of two children sued to get paid back-child support he claimed from their mother under a modified Louisiana domestic-relations order. He put copies of the orders in his first amended collection motion and simultaneously documented mailing copies of the old orders to mother. He clearly did not follow all the procedures of Texas Family Code section 159.602 to register out-of -state judgments under the Uniform Interstate Child Support Family Support Act.
The trial judge dismissed the case because the father never filed a separate motion to register the orders, and-- therefore-- the trial court lacked subject-matter jurisdiction.
Beaumont Ninth Court of Appeals justice Leann Johnson, wrote for a panel including Justices Charles Kreger and Hollis Horton reversing and remanding the trial court judgment because the father reasonably communicated to the trial court and to the mother that he wanted two orders registered and which they were. The Ninth Court of Appeals followed Kendall v. Kendall, 340 S.W.3d 483, 500-01 (Tex. App.—Houston [1st Dist.] 2011, no pet.) which held that failure to follow all the details of Tex. Fam. Code sec. 159.602 did not deprive the trial court of jurisdiction.
The opinion seems reasonable and will tend to simplify practice without depriving anyone of any material rights. The opinion notes that the father and his counsel were not present at the dispositive trial court hearing, but did not say why. The opinion put shudder quotes around the word proof in discussing the father's proof of mailing of the orders-- I am very curious why, but couldn't figure it out.
In re T.F. and T.F., (No. 09-14-00064-CV, Tex. App.-- Beaumont, Jan. 15, 2015) (mem. op.) (no pet. h.)