That makes a lot of sense, and it probably helped quite a bit in figuring out the series. The core of a cop's job and the crimes committed will remain essentially unchanged as time progresses, barring some upheaval in the social structure, but the method of the crime and the tools at their disposal will change. By leaving one thing the same and focusing on the rest, that grounds them in a way that makes it easy to immediately relate while also allowing them to explore interesting facets of a possible future.