Quoting Kelly +2 ERF/EH!:" Pediatricians don't know everything and you should always do your own research. You don't have to switch ... [snip!] ... to a booster when they outgrow one of the limits on a seat, buy a 3 n 1 to keep them in a harness longer. THAT'S whats safer."
that is like what my daughter is in, it converted into a high back booster... i know pediatricians dont know everything but most of them know the local car seat laws and if the child is to large for the car seat before the age the law requires the pediatricians can give a not to keep with you to show that it is ok for the child to be in the booster seat or at least thats how it is in va