Why do cartridge manufacturers give a range for VTF?

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.

Lyra Delos also has a VTF range; it's 1.7g - 1.8g with 1.75g being recommended. 
All that means is that they want you to start at 1.75g and move on from there. This is no different than any other manufacturer 

I agree with stringreen's argument while the reason is my Allaerts
MC 2: 1,8 g ( maximal tolerance 0,05g). However chakster's
''damping argument'' should also be of some importance because
the damper is behind the coils and, depending from its ''hardness''
should have some influence on the VTF. In my opinion Allaerts
demonstrate that getting optimal position of the coils is not an 
easy proposition. J. Carr wrote about this problem as well his
solution to the problems by his new cartridges. His intention is
also to get those ''tolerances'' as small as possible. 

@slaw 

I've noticed that there seems to be a post removed almost every time I post. Do I have a stalker? A'gon is looking into it.

To ease your paranoia, at least in this case, it was me who deleted my own post when I realized I was reflecting on VTA and not VTF, therefore I was writing something totally irrelevant in a moment of brain fog.  I'm not saying you don't have a stalker but in this case it was just me ;-)

t_e_p, how did you delete your post?

Recently I posted a question, then the next day found my answer.  So I attempted to delete it but could not find a way.  No one had responded to it yet.  All I could do was erase the content and mark it "removed".