Sure it does. It lets you know that there is a high percentage of probability that you will be able to solve the problem with a fairly low number of rounds.
No, simple percentage historical data only tell you what the chances where in the past. It is your interpretation of the historical data, your assumption, that they project into the future.
Part of the way in which the percentage average is kept low is due to gun capacities. Low capacity guns introduce a bias into the data that keep the percentages lower.
You have also assumed that the problem will "solved" with that number of rounds. In reality, that number of rounds average includes those where the shooter, good or bad, lost of the fight.