In general, using the outer cable to push rather than the inner cable to pull is a Bad Idea. It makes the action less precise, and this is worsened unless the cable outer is cut and mounted as best it can be to minimize that loss. Of course, you loose extra points for having a U-shaped outer section with the U at the bottom, and if you don't run stainless inners you get another reverse bonus; and if you DO have all those things and you DON'T use oil then you deserve what happens.