That first shot says a lot about the setup and preparation of your complete system. And its all good. There aren't that many folks that could get that first shot that close, be able to spot it, make the necessary adjustment then make "the" shot. Good going.
I shoot LR in similar terrain. You were shooting over a couple of valleys and rises and wind lift 'could' have been the difference. Lift is a difficult on to see.
Based on this single event, would you:
A) Adjust your drop chart that minute amount?
B) Keep'r the way she is and see if there's a trend?
BTW, there seems to be much more than just a "guess" with the windage you used!