No honey in a summer may happen because you have a new hive, your hive is overrun with pests, robbers or disease, or the nectar flow fails. Like crop failures in agriculture, it happens sometimes.
I mean 40 - 80lb per year. Most of that may be during summer in most climates, but in subtropical and tropical regions, bees gather nectar all year. That is why I said “per year”. When I kept bees in the UK, our best crops were about 80lb per hive per year - last harvest in August. In California, where we now live, most beekeepers get only about 40lb per hive per year, as our very dry climate reduces the availability of nectar. You will see from the discussion above, that many Australians see much higher honey yields. It is all very climate-dependent and the only way to know how much honey you can expect from your Flow hive, is to ask how much honey local beekeepers get from their traditional hives. The Flow hive may give you slightly more honey than a traditional hive (because the bees don’t have to make so much wax), but your best estimate of harvest quantity will be from the traditional beekeepers around you.