CURIOSITY

I have three plants, that are all same age, same growing conditions, and all seeds came from what I had collected, so I don't know for sure if they are all the same variety or not.
My question is:
Between all of them, there is probably 10"-12" difference in height, and the largest and smallest seem to have flowers from tip to stalk on the branches, but the middle height plant of them seems to only be flowering near the main stalk, (pics 23 and 24)
Is this just a different variety or did I unintentionally do something different to this one and just not remember?