It actually becomes easier to compare higher level opponents due to much more numbers being needed to increase to get twice as powerful. For example, lets say you have someone who can beat an army of 500 base value of 1 humans. Someone twice as strong as this 500 person would need to be at 1,000, so you have a good grasp of how powerful the two are among one another if you stay within a thousand or so points. You could imagine someone with 750 points being as strong as the 500 plus 50% more power pretty easily. If you see a big difference then you can easily just have them get crushed and not worry too much about how badly they'd get crushed. Having a 1 pointer up against a 500 or a 1,000 would end the same so it doesn't really matter at that point unless they bring a whole lot of friends.

Most characters taking part in fighting would be much higher than 1, but if there was an army of 50 pointers then you can easily determine that the 500 should be able to fight 10 of them and the 1,000 should fight 20. Upsets do happen but they came up with some sort of a scale to try and better judge the outcome of fights.