Some law departments put out for bids from law firms more than one cluster of work in the same offering. The general counsel decides that if the department is going to soldier through a competitive bid process, it might as well include several pools of projected legal services, even if they are in different legal areas. Further, the larger fees induce firms to try harder. The exercise makes more sense for both the department and the firms, as more savings can be wrung from a large amount of spend. Bigger spend, even across unrelated areas of law, increases the value and therefore the logic of the process on both sides. Efficiency and economics support multiple bundles in competitions.
When bundles of work are on offer, the advantage goes to the law firm that can take on more of them, all other factors being reasonably the same. After all, why not deal with a single firm rather than two different firms. True, the evaluation process complicates and larger [read, more expensive] firms enjoy an edge, but the benefits from multiple-bundle competitions make up those consequences.