The D7200 manual says that in A or P modes, the ISO menu Minimum Shutter Speed is the threshold concerning if ISO increases or not.
It does also say that in Auto Mode that the camera will choose Minimum Shutter Speed based on focal length, but that is only Auto mode.
But also, page 104 of the free larger D7200 Reference Manual also says that if flash is used, Minimum Shutter Speed will be set to either the E1 or E2 menu, as applicable (E1 flash sync speed, E2 slowest flash shutter speed in A or P mode).
In general though... Auto ISO action is this:
In A mode, as the light becomes more dim, the shutter speed drops to maintain proper exposure. When the shutter speed hits this ISO Minimum Shutter Speed, then the shutter speed is frozen there, and the ISO increases instead. However, when the ISO hits the Maximum ISO specified, the camera still must try to maintain a proper exposure, so then the shutter speed must drop even more.
In A mode, this ISO Minimum Shutter Speed should be given careful consideration, because, any time ISO is actively changing (anytime between Minimum and Maximum ISO), this is the shutter speed that will be used, every time.
But for D7200, if flash, then also see E1 and E2 menus, per that page 104.