Hello,

I have a question with hypothetical examples:

Let's say I start and set the home point of a Phantom 2 on top of a parking garage. To clarify, the starting height of the drone will be higher than the ground that the parking garage is sitting on. Let's also say that I want to land the drone 25 m to the east of the top of the parking garage in a field that is 30 m below the starting point of the drone.  

Would I have to enter a negative height, to get it to descend below its starting home point height, to land in that field?

To cut down on what could be a lengthy answer...
Since you said P2 (not P2V or P2V+) are you using the iOS GS?
And are you referring to a waypoint mission?
Or are you referring to RTH?

When the phantom arrives the home point,it will go down slowly and  motors will stop spinning when the phantom arrive the ground.