Without knowing the Client it would be hard for me to judge on the fb/twitter ratio. If the twitter is feeding the facebook, and they don't have the right followers.. How engaging are they, -- there are too many factors involved to comb through...
I have two ideas for you to look through/investigate. I would think option two would be the easiest, but you wouldn't have your answer until your test time passed. The first option will be tasking, depending on your site traffic.
1) I would verify this information by going through Traffic Sources -
Sources and comb through all traffic, direct, referrals, etc and take
not of all the traffic listed in there. Compare that to your Social
2) Another way to verify this information is to use a URL shorten
service with analytics (bit.ly) And only use those short links for
Twitter. Compare this with your analytics information and see how it
Good luck to you. If you would like any further help or insight, please comment and I'll see what I can do for you.