Trying to figure out how karma works, my karma does 'add up'

In my profile it says I have 1 post karma and -1 comment karma (which equals 0 I guess?).

But if I look at my comments in the comments tab, it looks to me like there are 6 karma points and no negatives. I have 0 posts (but it shows I have 1 post karma?) ... not computing, starting to feel like Hal 9000.