Is assaulting Bunkers too hard ?

[wiggum]

Hi !

I currentl play the second tutorial (Utah) and have a hard time taking any of the VP's.
I think it is currently too difficult to assault bunker hexes.

Look at this example:


The Enemys inside the bunker consist of:
X Inf, Moral "D" (less then 10 men)
X Gun, Moral "E" (DISRUPTED and took gun losses)
X Gun, Moral "F" (DISRUPTED and took gun losses)

The Bunker is completely surrounded (but not isolated because there is a supply source on the bunker hex) by somewhat like 500 US troops and a dozen tanks and got assaulted 3 times already before my test assault.
I saved right before the assault, i assault with 180 combat engineers (Moral "D", Low Fatigue)
I reloaded the save and assaulted again, i did this 15 times and never was able to take the bunker hex, the result you see in the above screenshot is the best result out of those 15 tests.

What do you think, do i maybe misunderstand the abstraction of the engine ?
Is it maybe realistic ? I hardly believe a few low quality static german troops would fight to the last men in such a case...