Anyway, there is no reason to forbid the use of words, and concepts, from other sciences, as long as they are useful in the new context. Evolution is one more case. It helps in describing the way institutions adapt by themselves and, in some way, restrict opportunities. It also helps to understand why organizations and individuals have to create and develop new institutions. Finally, it helps to understand why Russia is not very different from the Soviet Union, despite external appearence.
Interpretation is, in fact, the key to variation in institutions.
Rules of the game change because they are interpreted in different ways. Rules may be interpreted in a variety of ways, some survive, some not. There is evolution in rules. Interpretation reproduces, organizations and individuals are the environment which kills or enforces the breeding.