Will, it appears the Highest correction lightens the whole image, even a little in the center. My two photos were taken within seconds of each other at the same exposure.
Leica has built in vignetting correction in their M8 and M9 digital bodies. They use a built in lens table which identifies which lens and how much to correct based on a 6 bit code painted on the lens mount since none of Leica's rangefinder lenses have CPU's. Nikon's system seems to be better since you can control the level of correction.
And no problem with my trees. Three of them fell on the house but since they're Arborvitae with very soft branches and close to the house they didn't do any damage. It's just the expense of getting them out of there. The biggest problem is it's delaying my getting a new AFS 70-200mm VR II lens for a couple months.