If you anchor higher with three under, which is what most do when they switch from split finger, it reduces your mechanical advantage and it should be slightly more difficult to draw the bow. On the other hand, if you anchor lower than you did with split finger, you would increase your mechanical advantage or drawing arm alignment and should be able to draw a little more weight. In short, a higher anchor point usually leads to a higher drawing arm elbow, which reduces the amount of weight one can draw, and vice versa.