I've weighed out bags before, and they're rarely ever .1 ... ever. I mean, the pre-packaged, stamped and taped bags around here never, ever come out to .1 or anything close; we get two types of bags over here, what I call "jersey bags," which are just a tiny bit, only a hair, maybe just a fraction of an inch smaller in width than the other bags -- which I refer to as the "new york style" bags.
The "jersey bags" are usually stamped really generically, most often just some text like "24/7" or "FIRE" in either red or green or blue, sometimes with a graphic but not always, and they are pretty sloppy most of the time, most likely because they're coming from those heroin mills that punch out a million of the fucking things in a day. These bags always have the smallest amount of powder and it's never .1 -- ever. They sell them for a reasonable price in jersey, considering the amount of powder in the bags, but over here they sell for the same price as all the other bags which kind of sucks.
The "new york style" bags are, as I've said before, just a tiny bit wider than the "jersey bags" and I mean physically-speaking the bags themselves are a tiny bit wider, but they also contain more dope. These bags are closer to being on point but even they rarely ever come out to .1 (100 mg) It's more like 60 or 70 mg. The aforementioned "jersey bags" are more like 30 mg. The "new york style" bags are much more professionally done as well with graphics neatly stamped and taped and all that.
I see one guy who bags it himself, and those bags are usually pretty on point; I haven't weighed them, but I would say that they're pretty close -- maybe 80 or 90 mg if not the full 100. I think that's the only real way to get the on-point bags, by seeing someone who bags it up himself or herself and takes care to put a good amount in each bag.