I can see how exposure to additional math content should improve a kid's score on the same level of the SCAT math, but I don't think that you can really say the same for the verbal section. The SCAT verbal test covers only one type of language arts question--analogies. A kid could be learning quite a lot of useful language arts skills and content without any noticeable improvement in their ability to solve analogies. I would not be concerned.
I would totally agree with that. The SCAT is not extremely informative IMHO. Especially, that verbal section. My child scored high enough for awards in both areas. But a few months after that I had oral achievement testing done for some "real" data which was vastly more complete and informative (we homeschool so testing is required). I'm not sure I would use SCAT scores on their own to make any big decisions or for planning purposes. It was helpful to see similarly high scores on a couple other much broader achievement tests.