I added medium supers to the bottoms of two hives--
What am I missing?
You are missing one way....
It seem that you have good flow, and bees need room for honey, wet nectar, pollen and brood.
One way is that
- collect all honey and nectar frame up and
- and move brood frames down.
- Then add empty combs or foundations to boath boxes.
Often I do so that I add one super up and another down at ame time.
If you have pollen frames, the order is - brood- pollen - empty- wall
Don't brake brood area with empty frames in a small hive. 4-box hive stands braking.