I know this has been talked about before but I will bring it up again:
I would really really love to see some kind of feature that would allow the price (by formula) to remain variable until the time when the physical meeting takes place.
Fixing a price days ahead of time will always leave one party disgruntled. It helps noone. It also increases the occurence of people just not showing up greatly. Adjusting the amount of fiat cash involves cumbesome calculations (I did this today).
That would be nice, although I've been able to avoid the problem by not accepting orders that can not be completed within a few hours.
If somebody opens a contact and we can't meet right away I just ask them to close the order and open a new one immediately before we agree to meet. It also helps to exchange cell phone numbers after initial contact to help coordinate that.