This statistic, when playing South Korea, is currently not affected by enough factors. It should be reduced by:
Technology being high. One of South Korea’s main real-life advantages over North Korea is superior technology. Although it can be argued Military Spending to some degree represents the level of sophistication of military hardware purchased, a more technologically literate population is going to be able to use advanced military tech more effectively, with less extra training, and likely such a nation will have access to more sophisticated military equipment at a given price-point (thus giving Science Funding, for instance, a realistic link to national security).
National Service. Especially given that the North/South Korea conflict is a matter of posturing, rather than actual military effectiveness, having a larger military enlarged through widespread conscription gives South Korea and advantage. Canceling National Service outright (which S Korea starts with) should make the situation worse, whereas raising its implementation strength should make the situation slightly better. This is also true even if combat power were the truly important matter: North Korea’s army is comprised of huge numbers of poorly-trained draftees: so being able to match and even exceed the size of that army with better-trained and equipped South Korean draftees should absolutely convey security advantages.