I would say "all done!" and end the feeding when it seemed like Joe was more into throwing than eating. At this age, he also HARDLY ate solids. But lengthening feedings just meant more stuff on the floor, not in his mouth. He didn't really get into solids until he was closer to 15 months. I also have dogs, so that helps (way to get your dogs to LOVE your gropey, crazed toddler!), but at some point, it would just be clear that eating time was over.