Shutting one engine down on a two engine airplane to conserve fuel with revenue on board isn't the most intelligent thing in the world. Though I did once overhear a rather humorous exchange about just such a thing when a Twin Otter was holding over some airport in the bush and wanted to stay overhead for a bit longer than he could have running both engines.
No sane operator would have shut an engine down on a DC-9 to do this and on the 727 we definetly do not do that.