If you have eight frames in a ten frame box, they will build in the empty space. If you are spacing the frames evenly across the box, they will fill in the extra space.
Perhaps first thing would be to cut the boxes down turning it into an eight frame super. You have to respect the bee space or they will close it up with comb. Any space larger than 3/8 inch will get burr comb. If the space above the frames to the inner cover is greater than that, they will fill it in.
That 3/8 inch space is for all around. Above the frame, below the frame, to the side of the frame.
If the space between the frames is too much they will tend to build cross comb in that space.