If your child is below the 50th percentile, that can be a concern. Schools won’t target a child as a problem until below the 20th, but as a parent, you should work with your child on the basics. But after the 50th, your child is fine. Above the 80th, your child is strong.
At the early grades (k-4) high scores can be obtained because the test they are taking is primary and then elementary. As soon as they master that curriculum the score shown will be artificially high and cannot be compared with a high schooler.
Once kids switch to the advanced test (compacted 5/6 or Math 6, scores can start to be compared. Most kids in compacted math can definitely score higher, but again should not be compared to a child in calculus!
Be reasonable and just look for points growth each year.