LR Mobile Premium features don’t work on iPad

I have a paid subscription to the Creative Cloud Photography Plan and use LR Mobile on iPhone and iPad. Premium features (e.g. masking) work fine on the iPhone but not the iPad. Account information in both cases acknowledges that I am a subscriber.. I am up to date on LR version on both devices. I use the same Adobe login and email for LR on both devices, so I am perplexed about the iPad. Elsewhere I have seen a suggestion to click a "+" on upper left portion of the screen to activate these features, but I don't see a + sign! I tried signing out, signing no back in, etc., but no luck, so I'm looking here for help.