The "A" after your hubs mean there missing a summary. This summary can be unique or just a copy+paste of 2-3 lines from the hub. When the "A" is on your hub it means search engines summarize it for you (randomly collected sentences) This sucks because the bot normally doesnt put what you want people to read.
I even forgot to make a summary on many of my hubs, and now that I edited them im getting more traffic. This is due to the fact people searching for what you wrote about now get an idea if they want to read more or not. The title is important for indexing but the summary is important for people to decide if they want to click on that title or not.
I strongly recommend to make a summary for each hub! Sometimes you could get more pageviews just buy changing the summary from time to time to see what works best for a month on each hub. Its like tuning the title.
Hope this fully clears it up,