The important point in finishing the Iran-US deal before July 9 is not to give the US Congress a chance to get to review the deal for 60 consecutive days. Negotiations in Vienna are on in this direction.
There still are some important differences that are to be ironed out before the final deal can be inked, but negotiators in both parties are ready to hold time to ransom for a few days.
Negotiators fear giving the Iranian government enough time to rake up more issues than they can handle. They hope to conclude the business in a few days rather than return to the US without anything positive.
They shall not be able to do anything positive in this context for a long time. The momentum behind the deal is more likely to be erased by the time the team is behind the negotiating-table again.
Negotiators have set up a deadline of July 9 to be able to submit the papers to Congress in time for the July 10 deadline. An extension in the deadline is not going to be in anyone's favor. The Congress is more likely to enjoy a 60 day review period.
Among the points of contention is the question of the embargo imposed by the UN Security Council that bans supply of arms to Iran. The Russians are in favor of a phased removal of the embargo.
The arms embargo is being delinked from the concerns for nuclear non-proliferation. The embargo can be removed at a point of time in the future if significant progress is achieved in fighting militants.