Pretty much this. It's confusing because everyone, and every company, can do something different. As far as I know, there's no universal, enforced-by-law, commonly-accepted definition for "net carbs" so it's essentially a marketing thing.
Some companies may or may not count fiber in "net carbs", some may or may not count sugar alcohols, I vaguely remember reading some crap magazine talk about how whole fruit doesn't count toward daily "net carbs" because they're "unprocessed".
Your best bet is to decide what rules/guidelines you're going to do for you and your nutrition, and stick to it. Similar to how most/almost all people don't count the protein from oatmeal or potatoes in their "net protein" for the day, or some may or may not count the fat in their skinless chicken breasts or spray cooking oil in their daily "net fat" intake. Figure out what you'll apply to yourself, based on how much time/effort you want to invest in tracking things, keep those rules intact, and make adjustments as needed.