In the meantime, there has been labor peace. Sometimes, it is negotiated down to a single sticking point. Beyond that, it is deliberately left undefined, for the sake of getting a picture produced before options run out on story, financing, services of actors. If the picture flops, under any view, there is no problem. The risks of ambiguity were calculated, as the calculated risks of D-Day invasion.
Pressures change dramatically when the anxieties are unequal.
It makes a tremendous difference whether you write for those who have the leisure and bargaining power to work out all the details, or those who are oppressed with the burden of quick agreement. Whether they know it or not, we have to make this deal. If it must be done quickly, consider in advance of the writing what your client will not give up, and what is legally necessary. The plan for writing must reflect those decisions. Within those limits, the strategy of quick agreement dictates the writing and re-writing.