Difference in scoring algorithm of Powerprep practice tests and actual GRE

GRE General
1

I got 35/40 questions correct for quant in Powerprep 1 Practice test. The score was 163. Greg says in his “Powerprep 1 Verbal - Section 1” that you need to get around 32/40 correct for a score of 165. WHAT??? I got 2 less points for 3 extra correct questions?
Is scoring different in actual GRE from Powerprep 1 Practice test?
What’s the difference?
What should be approximate score on actual GRE for 35/40 correct answers?

2

See PowerPrep test