For a selected range of domains (around 200), I have tried -for 2 years now- to set the price to 80% of what GD appraises it.
No noticeable difference in the inquiries I'm receiving, in that, I see similar activity on those with GD pricing and those with higher than GD.
I have come to realise that, if someone wants a domain, they will act the same no matter what price the domain has, ie. they will find a way to contact with a lower offer (eg. via the registrar or whois, etc.) even on domains with a BIN and bargain from there.