Did you ever confirm the zoom on the Apex 50A? You said your's was a pre-production model...
The 50A in this video is not pre-production. In fact this is the same unit that's in the rental program. The XD38 unit with PIP was pre-production, but that was only available for a few days to demo and some of the videos on your YouTube are from that XD38 unit. The Apex XD50A definitely has 4X digital zoom. I can't tell you for sure is the 50S models will have 4X digital because there have been 0 production models delivered. A good guess would be that they have 4X digital zoom, but that's just a guess. It's confusing and I wish I had more concise and accurate info to share, but we are really just guessing until I have one in my hands.