Yes, they're more difficult. It's pretty common for people to score 1-3 points higher on the real thing than on their Kaplan tests. The same goes for TopScore tests as well. Naturally, though, there are exceptions.
the way how you score in your practice is not always so accurate. some do better in the actual and some dont.
however, PAT is a little harder (in my opinion)
just take the test when you think you have too much info in your head or you are going to start forgeting what you studied a couple of week ago and start to panic