Why do cartridge manufacturers give a range for VTF?

Threads themselves can be deleted and removed by the OP for sure, unless Audiogon changed that in last few days.
Done it myself on more than one occasion.

Agree with Chak that most carts have a range but then there will usually also be a recommended number, invariably pretty much in the middle of the range.

I just shoot for that middle ground number every time or slightly higher.