Claisen ester condensation: what's the point of the second deprotination, and then reprotination

In the formation of a beta keto ester and ethanol from 2 esters, like this:

http://upload.wikimedia.org/wikipedia/commons/0/0b/Claisen_ethyl_acetate.png

Apparently there is a further step, which involves further treating the beta keto ester with a base, to deprotinate the carbon inbetween the two carbonyls, and then reprotinate it with acid. I don't really understand the point to this.

Is is just so that when you deprotinate it, it the reaction won't go backwards, and then when you are sure that it wont go back after you remove it from base, you reprotinate it so you get a 100% yeild? I'm assuming that is the reason, but I am not completely sure.

The deprotonation at the end isn't intentional. It just happens by itself, because 1) you're running the reaction in basic conditions, and 2) the hydrogen alpha to the two carbonyls is fairly acidic. And, yes, it does help drive the reaction forward, since the resulting negatively charged product is stabilized by three resonance forms. We use the acid workup afterward to neutralize the product and any remaining base floating around.