Oh don't get me wrong. Its nice to know specs, but I hate how some provide just loaded and some provide unloaded and sometimes you can't tell whats what.
I am pretty sure about 1.73 (sgrt of 3).
As for rounding Kv numbers - that sucks.
As for loaded and unloaded Kv numbers that is BS, there is no way to compare numbers if you do not know the load. What they referring to is inertia, which is different for every motor brand/make. And what might be happening is attempt to subtract rotor losses from Kv ratings (just a guess).
As for program, it is open to add new files. And now anyone can create additional motor brands datasheets and share it.