Is homefield advantage determined correctly?

[Cipster]

I just noticed that in the Mogul Enthusiasts' my Yankees are playing Boston for the AL championship and Boston has homefield advantage despite being the Wild Card team and finishing second in the division.
Is that normal? Isn't the 1st place team supposed to get homefield? How is homefield advantage determined by the computer?

[sudden]

When I was the wildcard team and upset the top seeded team I received home field advantage. I think that the wild card never gets home field advantage during the league championship series. However, I don't know the official MLB rule on this.