Yes I agree, sorry I thought people were just talking about a light pack. By that measurement, the Ikea bag is in a similar situation. It doesn't look much larger, maybe 22L?
I think its more like 30; look at the picture with the full stuff sacks. those are at least 7L stuff sacks, there are two of them, and theres room for 2 more of the same size. I backpack with a 32 liter and the interior volume looks comparable.