When my child was first grade age I gave him the 2nd grade CAT. I did the out of level testing because I wanted to learn something from the results. A bunch of 90+ %iles would tell me nothing. As it turned out I didn't learn anything of value anyway. That was a surprise. I really expected it to be more challenging for him.
Friends have told me that the CAT is the easiest of the nationally normed tests. Many prefer the IOWA instead. This year we may do the SCAT (out of level for a talent search).
Of course, I don't have to give test results to anyone, so I didn't choose the test/level from that perspective... just for our personal info... YMMV.
Kate