Usually I see same plants with several different names. Can't tell 'em apart if the world depends on it. This may be the opposite, less usual circumstance. Even if it's only a cultivar level of difference, there are definitely different looking plants, if it's not just a juvenile vs. mature thing. If they are different, one of them could be needing another name, so they can be referred to uniquely. With so many plants, the slightest change gets a new cultivar name. The way these plants are all glommed without any cultivar names to sort them, if that is what would be appropriate, is interesting.
This pic makes it looks like the leaves can change a lot with age, condition, reverting or sporting, not sure what:
