Number of bullets divided amongst the men incorrect (Spoilers)

Overall, this is a pretty entertaining movie, though the characters make incredibly stupid decisions (I guess that was the point though).

However, one thing that really bothered me was the number of bullets divided from Reece's stash. They carried M16's with the 20 round magazines, and Reece pulls out a 20 round box of 5.56mm cartridges. You can clearly see the rounds when he removes them from the box (though if you pause it, you only see 9 rounds in the bottom row or 10, you can clearly see that there are 10 slots by 2 rows in the box. When he dumps them in his hand, one round from the bottom row must have been grabbed as well). Also, not to mention, it is implied he completely empties his rifle before reloading, and then when he chambers the rifle, you can clearly see another round (presumably a blank) fly out of the action(!). Okay, so he didn't bother checking the chamber before reloading, but I can understand that one given the circumstances...

Okay, so everyone gets 2 bullets. There are 8 guys. That is 16 bullets. That means there are four left over that just magically disappear. If I remember correctly, I think only 6 of them got a chance to actually use them. So, this is presuming that not only were there the missing bullets in the first place, but also that noone thought of removing the rounds from their deceased comrades' rifles.

Nitpicking, yeah, I know, but a story about survival that highlights several scenes about the severe shortage of ammunition should take all aspects of editing into account. This part really bothered the hell out of me about this film.

Anyone else notice this?