Ok great. For all their issues, they do well detecting chlorine presence, and if its trending up or down. So as long as the colors are making sense, the # doesnt really matter for 4 days. You have more than no chlorine in there. Add more if its getting low and adjust the dose amount reasonably as needed. Maybe 3 holds well, maybe you need 5 today.
Kinda funny that our 'barely enough knowledge to get by in an emergency' is probably better than most of the pools in the land. And we think its awful.