In the UK there is no law controlling the nutritional information shown of packaged foods. There are guidelines that allow at least +/- 20% leeway for each component (so an item with 10g of fat could actually have 8g or 12g), and being guidelines it doesn’t matter if it’s more.
That’s disappointing, of course, but what’s more surprising is that animal feed is tightly regulated; if cows ate Sainsbury’s prepared curry it would have to follow pretty closely what it said on the pack (to protect us, the ultimate consumer of the cow), but if we’re eating the curry, or the cow, it need not.