I think your sentences do plenty of work already. I see this advice at all levels -- scene, sentence, individual choice of words -- and always remember a moment during the heyday of the Scribblies. We were critiquing one of Steve's chapters, and for some reason everybody had picked on different words, scenes, sentences, and phrases as "unnecessary." Steve suddenly exploded, "What do you mean, necessary? THE BOOK IS NOT NECESSARY! Nobody will die if it is not written! Necessary to what?"

Most of us had to back off and admit to having become overly zealous in our attempts to create a lean mean everything; one sentence was, in the end, deemed unnecessary because it repeated information previously provided.

I think demanding work of sentences (or scenes) comes out of a similar mindset, and personally I am completely contented if my sentences do one job at a time. I like to save their overtime for significant moments.

P.