I redeemed the UHD code for Starship Troopers on MA rather than SonyPictures.com. This is a movie that's available in UHD on Amazon, UHD on Google Play (with HDR) and HDX on Vudu.
Vudu, as expected, was only SD. Support ticket is open with that.
Amazon did HD, but so far I haven't seen any UHD redemptions with Amazon as they keep their UHD titles under different headings. I intend to take that up with support at some point.
Google Play was a smashing success. 4k HDR from my Chromecast Ultra.
So, this is confirmation that MA recognizes that the codes from older Sony Discs are UHD and will grant access when appropriate.
It makes me annoyed at the number of Sony discs I already redeemed on UV. Great, I have UHD rights in that locker but I'll never ever get to use them unless Vudu adds those movies in UHD or unless Sony opens up its Ultra service to more devices. A number of those movies ARE in 4k and HDR on Google Play, so by redeeming the codes I screwed myself out of getting those copies. I'm going to contact MA to see if there's anything at all that can be done, but likely not. What makes matters worse is Google doesn't allow you to buy a higher version if you already own another version.
If the movie is UHD on Vudu as well, I'm still probably going to redeem on Sony Picture's site for the UV rights because UHD will push through to other services. But if a Sony movie doesn't have a UHD Vudu copy, then I'm better off at this point redeeming directly on MA.