6 or 8 hole, what's the diff?

I have both 6 and 8 hole flutes. They are all differant, so I can’t really compare say a PVC six hole Eb and a PVC D eight hole sound-wise.
I realise the 7&8 holes are remnants of stripped keyed flutes, but why are they still making the 7&8 hole on unkeyed flutes instead of just slicing them off at the 7 hole?
Is there really a sound difference? Or is it a matter of preference for the length and balance?
I haven’t seen this posted before, so I thought I’d throw it out and see what I get.
Thanks!
Terri

Somehow this topic managed to reappear a second time, if anyone know how to get rid of it, please do so, I don’t think I can delete it my side, please see other post with same name to respond. (this could only happen to me!)