Of course, we don't really know what that chart is supposed to describe. There's this "Star Ship Status", indicated in percentages of "completeness" that can apparently go past 100%, or have some sort of an appendix at least. There's the fact that NCC-1701 is at 85% or so. And then there's some poor NCC-1700 hovering around 11%...
It doesn't make much sense as an indicator of how complete a ship's repairs would be, as work on the NCC-1701 has not even started yet. If it indicates the condition of a ship, with 100% meaning functional, then why is NCC-1701 getting priority when there are others in much poorer condition? OTOH, why is a ship at 100% still listed at all?
This chart is the first time Star Trek makes the grievous error of assigning a NCC pennant prefix to all the ships presented, when real navies have the pennant letters provide information, with different letters denoting different kinds of ship. Of course, we later learn that Starfleet doesn't believe in providing such information; otherwise, we could use this chart as proof that all the ships listed there were at least of the same "mission class" (heavy cruisers or whatnot), and therefore perhaps indeed related to that "only twelve like her" thing somehow.
Apart from that, it might well be the starbase is processing a dozen ships (not necessarily repairing, but perhaps restocking or whatnot), and that their registries range from low 1600s to high 1800s in a "chronological" system, there not having been any bout of block obsolescence in Starfleet lately, but rather a steady evolution so that there are older and newer ships in service simultaneously.
It might also be that there are far more than a dozen ships there on that list, perhaps on other pages we are not seeing, and that not all of those have NCC prefixes, either. Depending on what sort of a filter Stone is applying, "all Constitutions" might be possible as well - but only if the list includes ships not physically present at SB11 at the time.
Timo Saloniemi