2 units in line of battle with each other lose a combat by 8.
As they are in line of battle, this is modified to 4 and both have to take a break test. They subtract the difference in scores from their cohesion value. Do they subtract 4 or 8?
If they answer is 8 then that means that any unit in a line of battle which has to take a break test will nearly automatically fail it (as they have to have lost the combat by at least 7)