The problem is that the northern and southern blocks of the top area are about 40% of the map IIRC. Holding that area until the last 15 seconds might work out in the favor of the team holding it. But only holding the top makes it easy for the other team to take the top by force due to having all of the bottom to hide.
A charger can cover over half the map not counting the topmost area with the crane. I have found that's the best way to go about winning the map.