If they don't live exactly where you do, it's entirely possible that they're right and you're "wrong" about what the label says. They might very well have put in exactly what their label says. Processed foods use different recipes and different ingredients in different places, and in some cases states have different laws about things like rounding or how exactly to calculate calories. Ten calories and one gram of fat difference probably means that in your area the manufacturer is allowed to round down where in other regions they have to round up. You might both have a product that has 3.5g of fat, but yours is allowed to be listed as 3 and theirs has to call it 4.
Or it might be that where the other members live, most of the cows are Jerseys, which give higher-fat milk, while the factory that supplies your store buys milk mostly from Holsteins.
It's a big country. Food is different in different areas, and one gram is a tiny amount.