I use the notch in the inner cover year round, not so much as an entrance, but more to help with ventilation, especially in the winter. It's just that at this time of year all the bees are up top and use the upper "entrance" because it's handy. They eventually start using the bottom more as the traffic builds up. I removed all my lower entrance reducers yesterday, as bees were balling up at the top and falling down to the bottom board in baseball size clusters.