I always apply the foot brake and hold the brake on so the car is totally stationary before putting in P........there are always reasons why not to do something on some car forum or other, but in the hundreds of thousands of miles of driving an auto, I've never exoerienced an issue with using only park as long as the car is stationary, before engaging or disengaging, and I have a quite steep driveway up hill slope into my garage....so all my cars are in P on the slope in P whilst I open the garage doors. It's a case of what ever you feel confortable enough with.
