When T is used, nothing is done to the pixels (->setting quality has no effect as the quality stays the same), it just writes the new resolution value into the header. Simple PhotoResizeD96T.exe should do that.
If T is not used, the tool tries to preserve the physical size of the image and calculates pixels or DPI automatically. If you want both, you'll have to do it in 2 steps.
_XL suffix can be added, but only if you are using it from command line with something like "-c<ROOT><PATH><NAME>_XL.jpg"