Does speed matter in journalism?

How is the success or failure of the “investigate story” activity determined? Does it matter how long it takes you to investigate?

The first time I tried it, I just squeezed in some investigating on nights when I wasn’t going out, and the story was a dead-end. I then made investigating my next two stories my main priority and finished them quickly. Both were successes, but my friendships suffered. I then tried to repair the friendships while working occasionally on another story, so it took longer to finish. This was again a failure.

Does this show that if you finish a story quickly it’s more likely to be a success? Or was it just a coincidence that it happened that way for me.

Also, I my most recent save has the story at 94% completion with just one more session of work to finish. When I got the dead-end result I reloaded, did something else that night, then tried finishing the story again the next night – with the same bad result.

Is there any point reloading and trying again on the next night and the next, or have I permanently run out of time on this story, so I’ll get a dead-end no matter what I do?