I think some people misinterpreted the question. 1/focal length is the rule of thumb for handheld shots. On a monopod, your technique and ability to hold still will be the deciding factor. The monopod by itself doesn't allow you to go to 1/focal length plus. Although the monopod will prevent movement of the camera on the vertical axis, you will need to look for horizontal and rotational stability, too. Depending on the shutterspeed, you may be able to do this yourself. Typically, people can improve their shutter speed by one or two stops.
Although people do stand straight up - feet together with a monopod exactly perpendicular to the ground - it's not an optimal position if you think about it. Generally, I try to "complete the tripod" - one leg is the monopod, one leg is me, and the other leg is something else like a chair or wall that I can lean against... my hands are the mount. If there is nothing to lean on, then I spread my legs out at shoulder-width for a more stable base.