Professional installers often use a towel to help steady the base. It would be impossible to make a base that fit perfectly with every type of carseat out there.

Looks like the testing has changed. I am sure the Royale that we got for DD1 and are still using for DD2 was quite well rated when we purchased it, but now it is quite low on the list. On the plus side the Baby Love seat we got for DD2 for the second car rates very well.