Why are PTs 150+ so much harder?

I just took PT 150, and after scoring -5 to -2 for my timed LR sections for the past 2 weeks and improving slightly in my score for my RC sections I ended up getting around 10 questions wrong on both LR sections and was having trouble even finishing 3 LR passages in the time alloted. I had some trouble during the test, having to pause to move testing locations 3 times, so I assumed that was the problem. However, even on BR I find most of all the questions extrodinarily hard, almost like the writing style for the questions have completely changed from the earlier PTs. Is this an issue anyone else has been dealing with, and is it something I should expect on the upcoming LSATs?