Group comments don't work properly

I have configured the widget to show 10 comments (0 trackbacks), group at most 2 comments and show first the recent comments.

You can see my widget now: http://i61.tinypic.com/295yee0.png

Some post althought has 2 comments only shows 1 (the latest of these).
In total widget shows 11 comments.

Why?

Thanks.

https://ww.wp.xz.cn/plugins/bwp-recent-comments/