It's just a number :-) Look past the number and start sucking in the bigger picture of yikes our path with be different. We had the same experience with the picture completion. Our dd then 4.1 kept saying your story is boring - let me tell you my story. Not surprising her processing speed wasn't high - her verbal ceilinged out but she didn't transition to the "non-verbal" without still being verbal :-)
I will say for the zooming part... remember it is all a comparision. Some parts he took more time on other kids might not even be able to get right... the mazes or symbol search stuff (maybe I'm making this up) might be something kids can do just not as fast.
Be sure to make a list of questions for your follow-up session... it is easy to get distracted with the conversation of what this will mean in life beyond the number that you may forget.
