How can the bees retrieve the excess honey left in the bottom channel of the frame, after extraction ?
If your hive is tilted 3 degrees toward the back then the honey in the channel will drain out the flow tube-- it just takes a while.
@FrederickDunn explains this issue and what can be done in his latest YouTube channel video.
If you have honey in the draining chamber after extraction then providing the ‘feed back slot’ is clear the bees will take it up and put it back into frames. Not into the frame it drained from as the bees need time to clean up the cells and reseal the slots in the cells, but they will store it elsewhere.
Make sure you have at least 3 degrees of tilt to the hive towards the rear and don’t rush the extraction. I extract 3 frames at a time via plastic tubes into a pail with a lid and bee proof holes in the lid for the tubes which I leave over night with the frames open and in the morning find a lot of extra honey in the pail. In the morning I close the frames and disconnect the tubes and close up.