the recovered solid would be more than the pure benzophenone should have been in the layer??
yup. Although I would make the following change:
the recovered solid would
be more have a greater reported mass than...
It's not that you have more benzophenone, it's that you have an impurity. Thus your mass recovery is greater than 100% - not because you created matter, but because the assumption that your material is one pure compound is flawed.
some were lost when pipetting the aqueous layer out
Sure. there are a number of reasons. Go through your proceedure as it is supposed to be done in perfect technique and check your assumptions. If any of those assumptions are wrong, you can introduce error. For one example, the procedure may begin by saying 'measure out 1 g of acid and 1 g of benzophenone and dissolve in ether.' Maybe you only measured out 0.95 g of benzophenone. You complete the procedure under the assumption that you are working with 1 g of benzophenone. In the end, you only recover 0.95 g. It would seem like you have a low yield, but your assumption was wrong.
I should keep washing the combined aqueous extracts to remove impurities
Are you sure it's the combined aqueous extract? or the combined organic extracts? If you wash the organic layer several times with water, that means you have to separate the layers each time, then add more water. What assumption do you make about that physical act of separation? How might a flawed assumption introduce error into the procedure which would cause the mass recovery of benzophenone to be low?