The reason the car would roll more sometimes than others is because it depends how close the pawl is to catching the next window before it engages. If it is almost lined up with a window or already lined up, there will be very little roll at that time. If there is a larger amount of distance it has to the next window engagement, then the car will roll more before th pawl engages the next window. This is normal behavior for park.

As stated above, you can adjust the parking brake.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record