As Mark is an admitted amateur/newbie at this, and he’s mentioned that he didn’t do anything differently this year,
How many times have we all baked a cake or brewed a batch “Just like last time”, but still had things come out different?
If all things are the same, the outcome will be the same. If all things aren’t the same, the outcome will not be the same, whether or not we recognize all of the factors at play.
Part of mastery is recognizing the factors enough to influence outcomes if we choose.
if he had less bees last year, they might not have filled up the entire hive with brood comb?
That’s not a bad theory at all.
I would think that a colony, even unmanaged, should be able to expand it’s nest to 24 frames in a season - But I am speaking from my regional experiences, and can only speculate as to the dynamics in his area.
I like your theory in principle, and allow me to suggest a twist: The expansion, contraction, and movement of the brood nest meant that the comb was at one point used for brood - It may not be a case of the nest having occupied the entire 24 frames at on time.
That being said, a fixed hive of 24 frames is too small and is no appropriate for a population of dynamic size that grows as large as it can when it is able, and stores as much honey as it can, when it is able.
Contrast this to my own hives, which use roughly that size as a baseline, and triple in size when the bees need the space to store honey. Were I to keep the size static and small, the bees would soon be in a crunch and constantly scrambling to find room for both babies and honey in a space the barely has enough for either, much less both.
On a related note I’m actually a little puzzled by this “24” frames, given that he’s using a Lang, and Lang frames are used in sets of 10. Strange.