I agree 100% with Bob’s comment above, the amount save is very relevant to the market price.
Here are my thoughts.
The asterisk notes were much easier to spot as something out of the ordinary, and in-turn more were saved.
The EHX are replacement notes, and are also know as a changeover prefix, where there are two signature varieties known. Once a changeover prefix is spotted, it is much easier to hold onto the new signature variety, then to find the older ones.
What I can assure you is that when I was looking for a L-B EHX, it took me along time to find a suitable note for my collection, where as the C-B EHX seemed to always be available.