Just to help muddy the waters

, here's a concept I recall reading a few years ago.
In this concept, there is the designation Heavy Cruiser, which refers solely to a hull design, i.e., the primary saucer, dorsal neck, roughly cylindrical engineering hull, and two warp drive units on long struts. The Mk "X" denoted the equipment that was installed in that hull. There were explorers, for instance, potentially with fewer weapons and better sensor suites. I can't recall the other types that were listed, but it let's say it was something on the other of combatants, having more firepower and defenses, priority response ships, with faster drivers, etc.
This may or may not have anything to do with the concept of what a "starship" is. Given the "12 like her" line, however, it would seem likely that starship would refer not to the hull, but to the mission outfitting.
The point of all this is that, in this paradigm, you could have a number of ships with the same hull but which were outfitted for different missions. Personally, I tend to not prefer this notion. I'm an old school tech guy who really likes FJ and his paradigm. Nonetheless, I have to admit that this can explain a lot of issues. 1017 could be the same hull with less defensive and offensive equipment, for instance. Instead of 4 of the most powerful ships in the fleet having been brought together to test M-5, there might have been a cross-section of different mission types to represent a typical fleet configuration.
By the way, if anybody can point me to the originals for this information, I'd be thankful. My memory says that it might have been something from Jeffries, but I'm not 100% on that, and it could have been just some fan speculation.