Major differences from PTests 42-61 from 62-71

As the title suggests, what are the definitive differences from these practice tests?

My lowest score was a 175 on 42-61 with an average of 177.

I come into 62-71, and I'm averaging 173/174 with the occasional 178+...

I've literally been studying more... I'm hoping to find some major differences I can focus on.