the bigger problem here is the level of ROLE play happening I believe.
If you have a well structured mission for your team, it really shouldn't take more then 2 hours for all the dice rolling, calculations, and number crunching to wrap up. (if you have more then 2 hours of rolling dice, time to scale things back a bit!!) that leaves 2 hours for the actual social interactions (role-play).
But, some people take longer... I have had entire games sessions wasted as the players discuss each and every option available to them for over a dozen different scenarios that could come in the run.... In short, they over planned, over thought the run. Not to mention blew most of the run reward on gear they actually had no need to use. (like hang gliders!)
of course YMMV, but that is up to the GM to help control and monitor....
It's like in DnD when you have that player that insists on visiting EVERY blacksmith in a Water Deep looking for that extra copper piece for that rusty battleaxe he took from a Kobald.... even though you tell straight to his face, that he will only get <x> amount.