That sounds like some real good shooting. I'm surprised that your point of impact shifted that dramatically with the Gold Dots, but I guess it happens. I'd love to try some BH209 but the price is still turning me off, plus I have a couple pounds of 777 to burn up first
The .40 cal 180 grain Gold Dots should be an excellent deer bullet. Last 2 seasons I've used the .40 cal XTP with great results, and from what I understand, the Gold Dots are an even more reliable construction. I'd guess that with 70 grains of BH209 your velocity should be 1800 - 1900 fps. That's a rough guess, but it should be in the ballpark. The Traditions manual states these velocities for a .40 cal 180 grain saboted bullet:
100 grains Pyrodex RS = 1900fps
100 grains Triple 7 = 2100fps
That should give you good deer-getting performance out to at least 100 - 120 yards. I'd go with it if you like it.