There's more to tanks than damagepoints and hitpoints.
A tank is strong. But a tank is brittle. It takes a good hit to kill a tank, a hit that doesn't kill it will likely do little damage. It only takes one good hit to kill a tank, and that one good hit will often destroy it completly.
It's also worth noting that the absolute weakest point of a tanks armor is the top.
Nothing strange.
(Note, rant into general complaints about GV model follows, as well as some monstrously bad paintbrush drawing)
This is what a tanks armor looks like(The thick part is the front) Drawn are hypothetical shots. The blue lines are shots which do no damage, the red lines are shots which in this case would be able to penetrate the armor. Note the relative thickness of the armor. Also note that the 'diagonal' shots have to pass through more armor in order to penetrate, the farther from 90 degrees that the shot hits at, the more armor it has to penetrate.
Now lets consider a couple cases of 1v1 tank duels.
On the left, we have one tank parked facing the rear of the other tank. This is a common case where you get such unbalances as hitting an identical tank 10 times, and then dying to the first shot. The tank on top has a huge advantage over the tank on the bottom who's weakest part is exposed.
In the next two we have the top tank at a 45 degree angle to the bottom tank. The bottom tank has nothing but his front armor exposed, while the top tank has both front and side armor exposed. The top tank's front armor may now be at a high enough angle that you have no chance of getting through it. So you'll need to aim for the weaker side armor.
Some of this is generalizations, some may be flat out wrong. Not intended for actual military use. Etc.
While the GV model isnt perfect, and has some real problems. The vast majority of tank complaints stem from a lack of understanding of armored warfare.
Two more points,
Tanks will ALWAYS turn to face thier enemy(when possible) in order to get thier strongest armor protecting them. In the same line of reasoning, a tank will always retreat in reverse, so as to avoid exposing thier weak rear armor.
