Below is a link to a team where Babe Adams was used as a "super reliever" in middle relief (Gossage was the closer), with mixed results by one of the best managers in the game. Adams made 99 appearances on the season, with just 3 starts.
http://onlinegames.strat-o-matic.com/team/sim/359451It's VERY RARE for a manager to use a S/R in relief all season, as it doesn't give as much bang for the buck as just using a pitcher designated as relief only.
In the above case, perhaps the manager was experimenting, trying to determine if he could get a few extra innings out of Adams in relief compared to other relief pitchers due to Adams' 5 inning endurance factor in relief.
My team was in the same division as the above team. I was concerned all season that any time Adams' team had a lead in the 5th inning or later that Adams would come in to shut the door, and while Adams had a good year, he wasn't unhittable.
In addition to the extra cost of using a S/R in relief, it's tough to maximize innings in a no DH league, as was the team above, as your star RP is subject to HAL's pinch hitting whims.
One is better off using a super reliever in a DH league, where, with the right settings, the relief pitcher will only get yanked if he reaches his point of weakness.