Not sure why people are blaming HFM for this name scheme. Seems more to be a Drop thing.
Drop is a supplicant in many ways. If Drop is speaking about a revival of the HE-500 you can bet your bottom dollar its all HFM spin. If Drop was leading in name designation why not label the HE-4XX as the HE-6XX? Well HFM didn't want them too, HFM instead built and marketed the HE-6se all on their own.