Hmm, I'm not really sure about those two variations in particular. Since the specs are the same, it may simply be architectural changes due to availability of parts or the like. Now that you've brought it up, I'd be curious to know more as well.
Unfortunately, there isn't a lot of info out there about the company or its products. I guess we, the PD product owners, need to start a wiki to consolidate whatever info we're able to find. I haven't even found documentation for all the supplies I already have.