My guess on why high profit loads are required:
As the (top 10) competitors are becoming niche and better, it is more likely for us to pick up underpriced policies, therefore apply a higher profit load protect us against it. All in all, if we have a super high profit load and not winning many policies, our profits will be close to 0 and enough to beat many other competitors. In other words, to beat the top and niche player, we need to be niche as well!