But after you set static VTF, in actual use the cantilever is moving constantly. How much is to some degree affected by tonearm inertia. So there is no one exact correct value for VTF. Also no two samples of any cartridge are exactly alike in terms of compliance. Another reason to provide a range of values.
Why do cartridge manufacturers give a range for VTF?
My Sussurros' manual says 1.8 - 2.2 grams. I know that Lyra, particularly the Delos has it rated at a very specific number. Just wondering, It would seem that the stated range would be very narrow.